ANATOMY_LC4_HEAD AND NECK, THORAX, PELVIS AND PERINEUM.pdf

ANATOMY UNIVERSITY OF NORTHERN PHILIPPINES SKELETAL SYSTEM: HEAD & NECK, COLLEGE OF MEDICINE, BATCH 2028 THORAX, PELVIS & PERINEUM...

ANATOMY UNIVERSITY OF NORTHERN PHILIPPINES SKELETAL SYSTEM: HEAD & NECK, COLLEGE OF MEDICINE, BATCH 2028 THORAX, PELVIS & PERINEUM DR LAWRENCE BUNDAL 08/28/2024 ▪ Calvaria – “skull cap” – vault of COURSE OUTLINE the neurocranium ▪ Cranial Articulations: I. BONES AND JOINTS INVOLVING THE HEAD ▪ Paired: A. Skull Parietal B. Bony Orbit Temporal C. Frontal bone ▪ Unpaired: D. Sphenoid bone Frontal E. Ethmoid bone Occipital F. Temporal bone Sphenoid G. Occipital H. Mandible Ethmoid I. Temporomandibular joint ▪ Facial Articulations: J. Nasal Skeleton ▪ Paired: K. Cranial fossa Palatine L. Cranial foramina Lacrimal II. BONES INVOLVING THE NECK Maxilla A. Cervical spine Nasal B. Hyoid bone Inferior nasal III. BONES OF THE THORAX concha A. Sternum Zygomatic B. Ribs ▪ Unpaired: C. Thoracic spine Vomer IV. BONES OF PELVIS AND PERINEUM Mandible A. Hip bone B. Pelvic girdle CRANIUM C. Sacrum D. Coccyx E. Sacroiliac joint The superior aspect of the skull encloses BONES and protects the brain, meninges, and cerebral vasculature. Specialized connective tissue made rigid by Subdivided into: the presence of inorganic salts (e.g., ▪ Cranial Roof (calvarium) – calcium phosphate) frontal, occipital, and two parietal Adult skeleton: 206 bones bones. Infant skeleton: >350 bones ▪ Cranial Base – frontal, sphenoid, Functions: ethmoid, occipital, parietal, and ▪ Protects the brain, spinal cord, temporal bones. ▪ articulate with the 1st thoracic, abdominal and pelvic cervical vertebra (atlas), organs ▪ Provides a frame that supports the the facial bones, and the body in an erect posture mandible (jaw) ▪ Provides an attachment for muscle and allows movement and locomotion I. BONES OF THE HEAD A. SKULL It supports the face and forms a protective cavity for the brain. It is comprised of many Figure 1. Bones of the calvarium and cranial base. bones, which are formed by intramembranous ossification and joined by FACE sutures (fibrous joints) also known as “viscerocranium” that ▪ 22 bones of the skull are divided supports the soft tissues of the face. It into 2 categories: consists of 14 bones, which fuse to house ▪ Cranium – cranial roof the orbits of the eyes, the nasal and oral and base cavities, and the sinuses. ▪ Face The facial bones are: Skull: skeleton of the head, including the ▪ Zygomatic (2) – forms the mandible 2 regions: cheekbones of the face and ▪ Neurocranium – portion of the articulates with the frontal, sphenoid, skull that encloses the brain temporal, and maxilla bones. ▪ Viscerocranium – facial cranium ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. ▪ Lacrimal (2) – the smallest bones of the face. They form part of the B. BONY ORBIT medial wall of the orbit. ▪ Nasal (2) – two slender bones Also known as “eye sockets,” they are located at the nose's bridge. bilateral and symmetrical cavities in the ▪ Inferior nasal conchae (2) – head that enclose the eyeball and its located within the nasal cavity, associated structures increases the surface area of the nasal cavity. BORDERS AND ANATOMICAL ▪ Palatine (2) – situated at the rear of RELATIONS the oral cavity and forms part of the hard palate. Roof (superior wall) – Formed by the ▪ Maxilla (2) – comprises part of the frontal bone and the lesser wing of the upper jaw and hard palate. sphenoid. The frontal bone separates the ▪ Vomer – forms the posterior aspect orbit from the anterior cranial fossa. of the nasal septum. Floor (inferior wall) – Formed by the ▪ Mandible (jaw) – articulates with the maxilla, palatine, and zygomatic bones. cranium base at the The maxilla separates the orbit from the temporomandibular joint (TMJ). underlying maxillary sinus. Medial wall – Formed by the ethmoid, maxilla, lacrimal, and sphenoid bones. The ethmoid bone separates the orbit from the ethmoid sinus. Lateral wall – Formed by the zygomatic bone and greater wing of the sphenoid. Apex – Located at the opening to the optic canal, the optic foramen. Base – Opens out into the face, and is bounded by the eyelids. It is also known as the orbital rim. Figure 2. Anterior view of the face, showing some of the bones of the nasal skeleton. The vomer, palatine and inferior conchae bones lie deep within the face. SUTURES OF THE SKULL a type of fibrous joint unique to the skull. They are immovable and fuse completely around the age of 20. Figure 4. The anterior and lateral views of the bony orbit. ▪ Coronal suture – fuses the frontal bone with the two parietal bones. Bony orbit contains the eyeballs and their ▪ Sagittal suture – fuses both associated structures: parietal bones. ▪ Extra-ocular muscles – These ▪ Lambdoid suture – fuses the muscles are separate from the occipital bone to the two parietal eye. They are responsible for the bones. movement of the eyeball and In neonates, incompletely fused suture superior eyelid. joints give rise to membranous gaps ▪ Eyelids – cover the orbits between the bones, known as fontanelles: anteriorly. ▪ Frontal – located at the junction of ▪ Nerves – Several cranial nerves the coronal and sagittal sutures supply the eye and its structures: ▪ Occipital – located at the junction ▪ Optic of the sagittal and lambdoid ▪ Oculomotor sutures ▪ Trochlear ▪ Trigeminal ▪ Abducens ▪ Blood vessels – The eye receives blood primarily from the ophthalmic artery. Venous drainage is via the superior and inferior ophthalmic veins. Figure 3. The major fontanelles and sutures of the skull BATCH 2028 1A 2 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. o Contains the supraorbital foramen, where the supraorbital vessels and nerve pass-through Figure 5. Diagram of the arterial supply to the eye. PATHWAYS INTO THE ORBIT Optic canal – transmits the optic nerve Figure 7. Anterior view of the frontal bone. and ophthalmic artery. Superior orbital fissure – transmits the The features of its internal surface include: lacrimal, frontal, trochlear (CN IV), ▪ Sagittal sulcus – vertical groove oculomotor (CN III), nasociliary and in the midline of the frontal bone, abducens (CN VI) nerves. It also carries the containing the superior sagittal superior ophthalmic vein. sinus. Inferior orbital fissure – transmits the ▪ Frontal crest – extension of the zygomatic branch of the maxillary nerve, sagittal sulcus edges (forms an the inferior ophthalmic vein, and attachment for the falx cerebri). sympathetic nerves. ▪ Groove for the anterior Minor openings: meningeal artery. ▪ Nasolacrimal canal - drains tears from the eye to the nasal cavity ORBITAL and is located on the medial wall are comprised of a triangular-shaped flat of the orbit. plate that extends posteriorly from the ▪ Supraorbital foramen and supraorbital margin – forming the roof of infraorbital canal – they carry the orbit (viewed below): small neurovascular structures ▪ Anterolateral portion consists of the lacrimal fossa (where the lacrimal gland sits) ▪ Anteromedial portion contains the trochlear fossa ▪ attachment for the pulley of the superior oblique muscle Figure 6. The major openings into the orbit. C. FRONTAL BONE one of the eight bones that make up the cranium – the superior aspect of the skull that encloses and protects the brain. Figure 8. Inferior view of the frontal bone, demonstrating its internal name is derived from the Latin ‘frons’, features. meaning ‘forehead’ NASAL Anatomical structure: an unpaired, ‘shell- Small area that projects inferiorly between shaped’ bone that forms the anterosuperior the supraorbital margins. aspect of the cranium. It consists of the four Area of articulation for the nasal bones and parts: squamous, orbital (x2), and nasal frontal processes of the maxilla. Supports the nose bridge SQUAMOUS ARTICULATIONS largest component of the frontal bone Houses the frontal sinus articulates with twelve other bones of the skull: separated from the orbital part by the ▪ Unpaired: ethmoid, sphenoid supraorbital margin ▪ Paired: nasal, maxilla, lacrimal, parietal, zygomatic BATCH 2028 1A 3 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. the tentorium cerebelli (the membranous D. SPHENOID BONE sheet that divides the brain). o Anterior Clinoid Processes - one of the eight bones that make up the arise from the Lesser Wing of the cranium – the superior aspect of the skull Sphenoid. that encloses and protects the brain. The sphenoid bone is said to be ‘butterfly- o Posterior Clinoid Processes- shaped. It consists of a body, paired greater are the superolateral wings and lesser wings, and two pterygoid projections of the dorsum processes. sellae. PARTS GREATER WING Body - located at the center; almost extends from the sphenoid body in a lateral, completely cuboidal in shape. superior and posterior direction. It Sphenoid Sinuses are separated by a contributes to three parts of the facial septum, meaning the sphenoid body is skeleton: essentially hollow. ▪ Floor of the middle cranial fossa Superior surface of the sphenoid body ▪ Lateral wall of the skull (Important Landmarks): ▪ Posterolateral wall of the orbit o Sella turcica -saddle-shaped Three foramina present in the greater wing: depression. It has three parts: ▪ Foramen rotundum- traversed by Tuberculum sellae- forms the the maxillary nerve. anterior wall of the sella ▪ Foramen ovale- allows the turcica, and the posterior passage of the mandibular nerve, aspect of the chiasmatic accessory meningeal artery, groove. lesser petrosal nerve and Hypophyseal fossa- deepest emissary vein. part of the sella turcica, where ▪ Foramen spinosum -traversed the pituitary gland is located. by the middle meningeal vessels Dorsum sellae- forms the and usually the spinous nerve, a posterior wall of the sella branch of the mandibular nerve. turcica. o Chiasmatic groove – a sulcus LESSER WING formed by the optic chiasm (where the arises from the anterior aspect of the optic nerves partially cross). sphenoid body in a superolateral direction. It separates the anterior cranial fossa from the middle cranial fossa; Forms the lateral border of the optic canal ▪ Optic Canal- which optic nerve and ophthalmic artery travel to reach the eye. ▪ Superior Orbital Fissure- ‘slit- like’ gap between the lesser and greater wings of the sphenoid. Figure 9. Foramina and bony landmarks of the sphenoid wings and pterygoid process PTERYGOID PROCESS descends inferiorly from the point of junction between the sphenoid body and the greater wing. It consists of two parts: ▪ Medial pterygoid plate – supports the posterior opening of the nasal cavity. ▪ Lateral pterygoid plate – site of origin of the medial and lateral pterygoid muscles Figure 10. Bony landmarks of the sphenoid body. Clinoid processes- surround the sella turcica (both anterior & posterior Clinoid Process) & serve as attachment points for BATCH 2028 1A 4 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. PARTS Cribriform Plate - forms the roof of the nasal cavity. It is pierced by numerous olfactory nerve fibers, which gives it a sieve- like structure. ▪ Crista Galli projects superiorly and provides an attachment point for the falx cerebri (dura mater Figure 11. Anterior and Posterior view of Sphenoid Bone sheet separating the two cerebral hemispheres). MUSCULAR ATTACHMENTS Perpendicular plate - forms the superior two-thirds of the nasal septum. lateral and medial pterygoid muscles, which Ethmoidal Labyrinths - large masses form some of the muscles of mastication, located at either side of the perpendicular originate from the lateral pterygoid plate plate containing the ethmoidal air cells. of the sphenoid bone. ▪ Orbital plate – the lateral sheet of bone, which also forms the medial ARTICULATIONS wall of the orbit. Sphenoid is an unpaired bone. It sits ▪ Medial sheet – forms the upper anteriorly in the cranium, and contributes to lateral wall of the nasal cavity. the middle cranial fossa, the lateral wall of the skull, and the floor and sides of both orbits. It has articulations with twelve other bones: ▪ Unpaired bones – Occipital, vomer, ethmoid and frontal bones. ▪ Paired bones – Temporal, parietal, zygomatic and palatine bones. Figure 13. The ethmoid bone within the nasal cavity. E. ETHMOID BONE ARTICULATIONS small unpaired bone located in the midline The ethmoid bone articulates with 13 of the anterior cranium – the superior others: aspect of the skull that encloses and ▪ Paired – nasal bones, maxillae, protects the brain; one of the 8 bones of the lacrimal bones, palatine bones, cranium. inferior conchae ▪ It is situated at the roof of ▪ Unpaired – frontal, vomer and the nasal cavity, and between sphenoid bones. the two orbital cavities. ▪ Contributes to the medial wall of the orbit and forms part of the anterior cranial fossa ▪ The olfactory nerve (CN I) is closely related to the ethmoid bone. Its numerous nerve fibers pass through the cribriform plate of the ethmoid bone to innervate the nasal cavity with the sense of smell. Figure 14. Anatomic relations and positions of Ethmoid bone F. TEMPORAL BONE contributes to the lower lateral walls of the skull. It contains the middle and inner portions of the ear and is crossed by the majority of the cranial nerves. The lower portion articulates with the mandible, forming the TMJ. The squamous, tympanic and petromastoid parts make up the majority of the bone. Figure 12. The anatomical position and relations of the ethmoid Zygomatic and styloid processes project bone. outwards. BATCH 2028 1A 5 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. ▪ Act as a reservoir of air, equalising the pressure within the middle ear in the case of auditory tube dysfunction. PETROUS PART ▪ pyramidal shaped and lies at the base of the temporal bone. It contains the inner ear. Figure 15. The constituent parts of the temporal bone. SQUAMOUS PORTION The squamous portion is the LARGEST PART OF THE TEMPORAL BONE. It is flat and plate-like, located superiorly. The outer facing surface of the squamous bone is convex in shape, forming part of the temporal fossa. The lower part of the squamous bone is the SITE OF ORIGIN OF THE TEMPORALIS MUSCLE. Articulates with the sphenoid bone Figure 16. Coronal section of temporal bone, showing anteriorly, and parietal bone laterally. the mastoid air cells in more detail ZYGOMATIC PROCESS ARTICULATIONS The zygomatic process arises from the A major articulation of the temporal bone is lower part of the squama temporalis. with the mandible, which is the Projects anteriorly, articulating with the TEMPOROMANDIBULAR JOINT. temporal process of the zygomatic bone. The squamous part also articulates with the These two structures form the zygomatic sphenoid bone anteriorly and the parietal arch. bone laterally. One of the zygomatic processes’ The zygomatic process of the temporal attachments to the temporal bone forms the bone also articulates with the zygomatic articular tubercle (part of the TMJ). bone to form the zygomatic arch. Masseter muscles attach some fibers to the lateral surface of the zygomatic G. OCCIPITAL BONE process. TYMPANIC PART OF THE TEMPORAL BONE The occipital bone is a flat, unpaired bone that forms a major part of the posterior wall Surrounds the external auditory opening, and base of the skull. which leads into the external auditory Protects the cerebellum and occipital lobes meatus of the external ear. of the cerebrum and provides attachment to several muscles and ligaments. STYLOID PROCESS The bone curves on itself and is trapezoid Located immediately underneath the in shape. opening to the auditory meatus. Contains outer and inner layers of cortical Attachment point for muscles and bone, with cancellous bone sandwiched ligaments, such as the stylomandibular between them. ligament of the TMJ. Three parts: squamous, condylar, and basilar. PETROMASTOID PROCESS The petromastoid portion of the temporal bone is located posteriorly. It can be split into a mastoid and petrous parts. MASTOID PROCESS ▪ Inferior projection of bone, palpable just behind the ear. ▪ Site of attachment for many muscles, such as sternocleidomastoid. MASTOID AIR CELLS Figure 17. Bones of the calvarium and cranial base. ▪ Hollowed out areas within the temporal bone. BATCH 2028 1A 6 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024 SQUAMOUS. CONDYLAR The squamous part of the occipital bone is The condylar part of the occipital bone the largest and most posterior portion. It forms the lateral walls of the foramen borders the parietal and temporal bones, magnum. It comprises two occipital and forms the posterior part of the foramen condyles and serves as an articular surface magnum. with the atlas (at the atlanto-occipital joint). CONDYLOID FOSSA Internal Surface ▪ Articulates with the superior facet marked by grooves produced by the dural of the atlas in neck extension. venous sinuses. ▪ Contains the condylar canal GROOVE FOR TRANSVERSE SINUS ▪ carry the occipital emissary veins that o Located either side of the internal perforate the bone to occipital protuberance. attach suboccipital GROOVE FOR SUPERIOR SAGITTAL venous plexuses with the SINUS sigmoid sinus. o Extends from the internal occipital Inner side of the condylar base contains the protuberance superiorly. HYPOGLOSSAL CANAL. INTERNAL OCCIPITAL CREST ▪ Hypoglossal nerve exits and a (OCCIPITAL SINUS) branch of the ascending o Extends from the internal occipital pharyngeal artery enters. protuberance inferiorly. Jugular processes projecting from the o It is also the site of attachment of condyles the falx cerebri. ▪ Jugular notch lies anterior ▪ Jugular foramen lies lateral to the External Surface hypoglossal canal marked by four bony ridges, known as the nuchal lines. They represent the site of attachment for numerous muscles and ligaments. SUPREME NUCHAL LINE ▪ Extends from the midline of the occipital bone towards the lambdoid sutures on either side. SUPERIOR NUCHAL LINE ▪ Marked in the midline by a palpable prominence – known as the external occipital protuberance. ▪ Site of attachment of the splenius capitis, trapezius and occipitalis. MEDIAN NUCHAL LINE ▪ Extends from the external occipital protuberance inferiorly in the Figure 19. External surface of Occipital bone vertical midline, towards the foramen magnum. BASILAR ▪ Site of attachment of the nuchal The basilar region of the occipital bone forms the ligament. anterior part of the foramen magnum. It INFERIOR NUCHAL LINE articulates with the temporal and sphenoid ▪ Transects the medial nuchal line at bones. its approximate midpoint, curving Internal surface marked by a broad, shallow downwards. groove called the clivus. ▪ Site of attachment of the obliquus o Supports the medulla oblongata capitis superior, rectus o Provides attachment for the tectorial membrane. Basilar part articulates with the petrous portion of the temporal bone to form the INFERIOR PETROSAL SULCUS. o Contains the inferior petrosal sinus. External surface o Longus capitis and rectus capitis anterior muscles attach to the basilar part of the occipital bone. Figure 18. External surface of the occipital bone BATCH 2028 1A 7 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. Figure 22. Internal surface of the mandible and its bony landmarks. Figure 20. Internal surface of Occipital bone The mandible consists of a horizontal body FORAMEN MAGNUM (anteriorly) and two vertical rami (posteriorly). The body and the rami meet on each side at the angle of The foramen magnum is a large opening in the mandible. the occipital bone. It allows passage of structures to and from the cranial cavity. Body - curved, and shaped much like a The medulla oblongata (part of the horseshoe. It has two borders: brainstem), accessory nerves, vertebral ▪ Alveolar border (superior) – arteries, anterior and posterior spinal contains 16 sockets to hold the arteries, alar ligaments, and the tectorial lower teeth. membrane all. ▪ Base (inferior) – site of attachment for the digastric muscle medially MANDIBULAR SYMPHYSIS a small ridge of bone that represents the fusion of the two halves during development. The symphysis encloses a triangular eminence – the mental protuberance, which forms the shape of the chin. Lateral to the mental protuberance is the mental foramen (below the second premolar tooth on either side). It acts as a passageway for neurovascular structures. Figure 21. Superior view of Base of the skull ARTICULATIONS The occipital bone articulates with two paired bones (parietal and temporal) and two unpaired bones (sphenoid bone and atlas): o Parietal bones on either side superiorly to form the lambdoid suture. o The mastoid portion of the temporal bone on each side inferolaterally forms the occipitomastoid structure. o Sphenoid bone anteriorly at the inferior angle. o Atlas (C1) inferiorly at the Figure 23. External and Internal Surface of Mandible atlantooccipital joint. MANDIBULAR RAMI H. MANDIBLE projects perpendicularly upwards from the angle of the mandible. Each ramus contains The mandible, located inferiorly in the facial the following bony landmarks. skeleton, is the largest and strongest bone ▪ Head - articulates with the of the face. temporal bone to form the TMJ. o The Mandible (jaw) articulates with the ▪ Neck - supports the head of the base of the cranium at the ramus. It is also the site of temporomandibular joint (TMJ). attachment of the lateral pterygoid o forms the lower jaw and acts as a muscle. receptacle for the lower teeth. ▪ Coronoid process - site of o It articulates on either side with the attachment of the temporalis temporal bone, forming the muscle. temporomandibular joint. BATCH 2028 1A 8 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. Internal surface of the ramus is also marked by the mandibular foramen which acts as a passageway for neurovascular structures Mandibular fracture - often bilateral, occurring directly at the side of trauma and indirectly at the contralateral side due to transmitted forces. Clinical features include pain at the fracture site and misalignment of the teeth (malocclusion). I. TEMPOROMANDIBULAR JOINT The articulation of the mandible and the temporal bone of the cranium forms the Figure 25. Ligaments in the TMJ. temporomandibular joint (TMJ). It is located anteriorly to the tragus of the ear, on the Movements are produced by the muscles of lateral aspect of the face. mastication, and the hyoid muscles. The TMJ consists of articulations between three two divisions of the TMJ have their own surfaces: functions. o Mandibular fossa and articular o Protrusion and Retraction tubercle - from the squamous part ▪ The upper part of the of the temporal bone joint allows protrusion o Head of the mandible and retraction of the Articular disk - separates the articular mandible: the anterior surfaces of the bones so that they never and posterior come into contact with each other. It also movements of the jaw. splits the joint into two synovial joint Lateral pterygoid muscle cavities, each lined by a synovial o Responsible for protrusion and the membrane. posterior fibers of the temporalis o The articular surface of the bones perform retraction. is covered by fibrocartilage, not o A lateral movement (i.e. for hyaline cartilage. chewing and grinding) is achieved by alternately protruding and retracting the mandible on each side. Elevation and Depression o Depression is mostly caused by gravity. o The digastric, geniohyoid, and mylohyoid muscles assist if there is resistance. o Elevation is very strong movement caused by the contraction of the temporalis, masseter, and medial pterygoid muscles. The arterial supply to the TMJ is provided Figure 24. Osteology of the TMJ. by the branches of the external carotid, principally the superficial temporal branch. o Other branches: deep auricular, EXTRACAPSULAR LIGAMENT ascending pharyngeal and Lateral ligament maxillary arteries. o Runs from the beginning of the o The TMJ is innervated by articular tubule to the mandibular auriculotemporal and neck. masseteric branches of the o A thickening of the joint capsule, mandibular nerve (CN V3). and acts to prevent posterior dislocation of the joint. J. NASAL SKELETON Sphenomandibular ligament o Originates from the sphenoid The nasal skeleton is a combination of spine attached to the mandible. bone and cartilage which forms both what Stylomandibular ligament we can see as the external nose and the o A thickening of the fascia of the internal nasal septum which divides the two parotid gland. nasal cavities of the head. o Supports the weight of the jaw. o The nasal skeleton is composed of two slender bones located at the nose's bridge. The skeleton of the nose is formed by three types of tissue: bone, cartilage and fibro- fatty tissue. BATCH 2028 1A 9 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. separating it from the oral EXTERNAL NASAL SKELETON cavity. It also consists of the palatine bone extends the nasal cavities onto the front of posteriorly, and the the face. palatine process of the o Nasal and maxillary bones- maxilla anteriorly. situated superiorly. ▪ Cribriform plate - forms o Hyaline cartilages - Inferior the roof of the nasal portion of the external nose that cavity. makes up: ▪ lateral, major alar, minor K. CRANIAL FOSSA alar, and the cartilaginous septum. o Lateral and major alar cartilages - largest and contribute the most to the shape of the nose o Minor alar cartilages - vary in number: usually 3 or 4 on each side. Figure 28. The cranial fossa. DIVISION Anterior cranial fossa is separated from Figure 26. Lateral view of the external nasal skeleton. the middle cranial fossa by the lesser wing of the sphenoid. INTERNAL NASAL SKELETON o formed by: ▪ Frontal bone separates the nasal cavity into two nostrils. ▪ Cribriform plate of the The bones that contribute to the nasal ethmoid with crista galli septum can be divided into: ▪ Lesser wing of sphenoid. The middle cranial fossa is separated from the posterior cranial fossa by the petrous part of the temporal bone. o formed by: ▪ Body of the sphenoid ▪ Greater wing of sphenoid ▪ Squamous and petrous parts of the temporal lobe ▪ Inferior part of the parietal lobe o Boundaries: Figure 27. Lateral view of the side of the nasal septum. ▪ A: Lesser wing of sphenoid ▪ P: Petrous part of the temporal o Paired bones - Nasal, maxillary and lobe palatine bones ▪ L: Squamous part of the temporal, o Unpaired bones: greater wing of sphenoid and ▪ Ethmoid - contributes to parietal lobe. the central portion of nasal septum. Posterior Cranial Fossa is bordered: ▪ Septal cartilage and Anteriorly by the petrous part of vomer - forms the Temporal. anterior and posterior Posteriorly by the occipital. parts. ▪ Hard palate - forms the Floor by the occipital and mastoid floor of the nasal cavity processes of the temporal. BATCH 2028 1A 10 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. Figure 29. Divisions of the cranial fossa. Figure 30. Superior view of the skull base showing the foramina and which cranial nerves pass through them. L. CRANIAL FORAMINA The cribriform foramina refers to numerous perforations in the cribriform plate of the ethmoid bone. They connect the anterior cranial fossa Cribriform plate with the nasal cavity. o Olfactory nerve (CNI) Allow passage of the olfactory nerve axons from Optic canal the olfactory epithelium of the nose into the o Optic nerve (CNII) anterior cranial fossa, where they communicate Superior orbital fissure with the olfactory bulb. o Oculomotor nerve (CNIII) o Trochlear nerve (CNIV) OPTIC CANAL o Ophthalmic nerve (CNV1) o Abducens nerve (CNVI) The optic canal permits the passage of the optic nerve (CN II) and the ophthalmic artery into the Foramen rotundum bony orbit. o Maxillary nerve (CNV2) ▪ Medial border: body of the Foramen ovale sphenoid o Mandibular nerve (CNV3) ▪ Lateral border: lesser wing of the Internal acoustic meatus sphenoid bone. o Facial nerve (CNVII) o Vestibulocochlear nerve (CNVIII) SUPERIOR ORBITAL FISSURE Jugular foramen The superior orbital fissure is a cleft that opens o Glosopharyngeal nerve (CNIX) anteriorly into the orbit, enabling communication o Vagus nerve (CNX) between the cavernous sinus and the orbit apex. o Accessory nerve (CNXI) Borders: Hypoglossal canal ▪ Superiorly - lesser wing of o Hypoglossal nerve (CNXII) sphenoid ▪ Inferiorly - greater wing of the sphenoid Transmits several structures (from superior to inferior): ▪ Lacrimal nerve (branch of the ophthalmic nerve, the first division of the trigeminal nerve) ▪ Frontal nerve (branch of the ophthalmic nerve, the first division of the trigeminal nerve) ▪ Superior ophthalmic vein ▪ Trochlear nerve (CN IV) ▪ Superior division of the Oculomotor nerve (CN III) ▪ Nasociliary nerve (branch of the ophthalmic nerve, the first division of the trigeminal nerve) BATCH 2028 1A 11 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. ▪ Inferior division of the Oculomotor anterior and posterior spinal arteries, and nerve (CN III) the dural veins. ▪ Abducens nerve (CN VI) ▪ A branch of the Inferior ophthalmic FORAMEN SPINOSUM vein FORAMEN ROTUNDUM Located within the middle cranial fossa, laterally to the foramen ovale. The foramen rotundum is located at the base of Allows the passage of: middle meningeal the greater wing of the sphenoid, inferior to the artery, the middle meningeal vein and the superior orbital fissure. meningeal branch of CN V3 Provides a connection between the middle cranial fossa and the pterygopalatine fossa. FORAMEN LACERUM The maxillary nerve (branch of the trigeminal Irregularly shaped foramen located at the nerve, CN V) passes through this foramen. junction of the sphenoid, temporal and occipital bones. FORAMEN OVALE Filled by cartilage – with only a few minor The foramen ovale is another opening located at vessels passing through it. the base of the greater wing of the sphenoid. Positioned posterolateral to the foramen rotundum within the middle cranial fossa. Conducts the mandibular nerve (branch of the trigeminal nerve, CN V) and the accessory meningeal artery INTERNAL ACOUSTIC MEATUS The internal acoustic meatus is a bony passage located within the petrous part of the temporal bone. Connects the posterior cranial fossa and the inner ear. ▪ Transports neurovascular structures to the auditory and vestibular apparatus. Facial and vestibulocochlear nerves pass Figure 31. Superior view of Base of the skull through this meatus alongside the vestibular ganglion and labyrinthine artery. II. BONES OF THE NECK JUGULAR FORAMEN A. CERVICAL SPINE The jugular foramen is formed anteriorly by the petrous part of the temporal bone and The most superior portion of the vertebral posteriorly by the occipital bone. column, lying between the cranium and the Three separate compartments with their thoracic vertebrae respective contents: consists of seven distinct vertebrae, two of ▪ Anterior – contains the inferior which are given unique names: petrosal sinus ▪ Middle – transmits the C1 ATLAS glossopharyngeal nerve, vagus first cervical vertebra and articulates with nerve and cranial part of the the occiput of the head and the C2 accessory nerve. ▪ Posterior – contains the sigmoid sinus and transmits meningeal branches of occipital and ascending pharyngeal arteries. HYPOGLOSSAL CANAL The hypoglossal canal is located in the occipital bone, through which the hypoglossal nerve (CN XII) passes to exit the posterior cranial fossa. OTHER FORAMINA FORAMEN MAGNUM Figure 32. The bony landmarks of the atlas Largest Lies in the occipital bone within the Characteristics: posterior cranial fossa ▪ no vertebral body Allows the passage of the medulla and ▪ no spinous process meninges, the vertebral arteries, the BATCH 2028 1A 12 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. ▪ It has lateral masses which are connected o Medial atlanto-axial joint by an anterior and posterior arch. ▪ formed by the articulation of the ▪ superior articular facet (for articulation with dens of C2 with the articular occipital condyles) facet of C1. ▪ inferior articular facet (for articulation with ▪ pivot type synovial joint. C2). ▪ Anterior arch contains a facet for o Atlanto-occipital joints articulation with the dens of the axis ▪ articulation between the spine ▪ Posterior arch has a groove for the vertebral and the cranium. artery and C1 spinal nerve. ▪ occur between the superior facets of the lateral masses of C2 AXIS the atlas and the occipital easily identifiable due to its dens (odontoid condyles at the base of the cranium. process) extending superiorly from the ▪ condyloid-type synovial joints, vertebra's anterior portion. and permit flexion at the head, i.e., nodding. SIX MAJOR LIGAMENTS Present throughout the entire vertebral column: a. ALL and PLL – long ligaments that run the length of the vertebral column, covering the vertebral bodies and intervertebral discs. b. Ligamentum flavum – connects the laminae of adjacent vertebrae. c. Interspinous ligament – connects the spinous processes of adjacent vertebrae. Figure 33. The bony landmarks of the axis. The dens articulates with the anterior arch of the atlas, creating the medial atlanto- axial joint o Rotation of the head independently with the torso contains superior articular facets, which articulate with the inferior articular facets of the atlas to form the two lateral atlanto-axial joints. JOINTS OF CERVICAL SPINE The cervical spine joints can be divided into two Figure 34. Ligaments of the cervical spine. groups – those present throughout the vertebral column, and those unique to the cervical spine. Unique to cervical spine: a. Nuchal ligament Present throughout the vertebral column : o continuation of the supraspinous Between vertebral bodies ligament. o adjacent vertebral bodies are joined by o attaches to the tips of the spinous intervertebral discs, made of processes from C1-C7 and fibrocartilage. provides the proximal attachment o a type of cartilaginous joint, known as a for the rhomboids and trapezius. symphysis. Between vertebral arches b. Transverse ligament of the atlas o formed by the articulation of superior and o connects the lateral masses of the inferior articular processes from adjacent atlas, and anchors the dens in vertebrae. place. o a synovial type joint. Unique to cervical spine Anatomical Relationships o Lateral atlanto-axial joints (x2) The transverse foramina of the cervical ▪ formed by the articulation between vertebrae provide a passageway by which the inferior facets of the lateral masses of C1 and the superior the vertebral artery, vein and sympathetic facets of C2. nerves can pass. ▪ plane type synovial joints. EXCEPT: C7 – where the vertebral artery passes around the vertebra, instead of through the transverse foramen. BATCH 2028 1A 13 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. attaches to the posterior surface of the hyoid bone and the greater B. HYOID BONE horns. o a ‘U’ shaped structure located in Hyoepiglottic ligament the anterior neck. It lies at the o connects the hyoid bone to the base of the mandible anterior aspect of the epiglottis. (approximately C3), where it acts as a site of attachment for the anterior neck muscles. Figure 35. Position of Hyoid bone in the neck COMPOSITION Body o central part o has an anterior convex surface and a concave posterior surface. Greater horn (two) o projects from each end of the body in a posterior, superior, and lateral direction. o site of attachment for numerous neck muscles. Lesser horn o arises from the superior aspect of Figure 37. Anterior view of hyoid bone with ligaments and muscles the hyoid bone, near the origin of the greater horn. o It projects superoposteriorly (toward the styloid process of the temporal bone). The stylohyoid ligament attaches to the apex of the lesser horn Figure 36. The major parts of the hyoid bone – body, greater horn ]and lesser horn The hyoid bone is unique because it does not articulate with any other bones, and it is suspended in place by the muscles and ligaments that attach to it. Stylohyoid ligament o extends from the styloid process of the temporal bone to the lesser horn of the hyoid bone. Thyrohyoid membrane o originates from the superior border of the thyroid cartilage and BATCH 2028 1A 14 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. The body is flat and elongated. It III. BONES OF THE THORAX articulates with the manubrium superiorly and the xiphoid process inferiorly. A. STERNUM lateral edges of the body are marked “ breastbone” is a flat bone located at the by numerous articular facets anterior aspect of the thorax. It lies in the o articulate with the costal midline of the chest and has a ‘T’ shape. cartilages of ribs 3-6. Helps protect internal thoracic viscera o Heart o smaller facets for articulation o Lungs with parts of the 2nd and 7th o Esophagus rib. Figure 40. Anterior view of Sternum The xiphoid process is the most inferior and smallest part of the sternum o variable in shape and size o tip located at the level of the T10 vertebrae o largely cartilaginous Figure 38. Anterior perspective of the Sternum o ossifies late in life (40 years old) PARTS OF STERNUM The manubrium is the most superior portion of the sternum. It is trapezoid in shape Superior aspect: o Concave in shape - jugular notch o Large fossa lined with cartilage ▪ Sternoclavicular joint Lateral edge: o Facet – articulates with costal cartilage of the 1st rib o Demifacet - articulates with part of the costal cartilage of the 2nd rib. Inferior portion: Figure 41. Anterior view of Xiphoid Process o Articulates with the body of the sternum → sternal angle. B. RIBS a set of twelve paired bones that form the protective ‘cage’ of the thorax. They articulate with the vertebral column posteriorly and terminate anteriorly as cartilage Protects internal thoracic organs Moves during chest expansion Figure 39. Anterior view of Manubrium with articulations BATCH 2028 1A 15 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. Rib 1 shorter and wider Only has one facet on its head for articulation with its corresponding vertebra Superior surface is marked by two grooves, which make way for the subclavian vessels Rib 2 thinner and longer than rib 1 has two articular facets on the head as normal. has a roughened area on its upper surface, from which the serratus anterior muscle Figure 42. Overview of the ribs and costal cartilage. originates. Head - wedge shaped and has two articular TYPICAL RIBS facets separated by a wedge of bone Neck - connects the head with the body. Rib 10 o roughed tubercle with a facet only has one facet The body, or shaft of the rib is flat and o for articulation with its numerically curved corresponding vertebra o It has a costal groove Ribs 11 and 12 have no neck only contain one facet o articulation with their corresponding vertebrae Figure 42. The bony landmarks of a typical rib. ATYPICAL RIBS Ribs 1, 2, 10, 11 and 12 have features that are not common to all the ribs. Figure 44. Atypical rib ARTICULATIONS majority of the ribs have an anterior and posterior articulation. Posteriorly, all twelve ribs articulate with the vertebra of the spine. Each rib forms two joints: o Costotransverse joint ▪ between tubercle of rib and transverse costal facet of corresponding vertebra o Costovertebral joint ▪ between head of rib, superior costal facet of corresponding vertebra and inferior costal facet Figure 43. Rib 1 of the vertebra above BATCH 2028 1A 16 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. ▪ Present in all vertebrae o Demi-facets on the sides of each except T11 and T12 vertebral body (T2-T9) ▪ Articulates with the heads of ribs superior facet articulates with the head of the adjacent rib ▪ Inferior facet articulates with the head of the rib below o Costal facets on the transverse processes o Articulate with rib tubercles Figure 45. Posterior articulations between a typical rib and its o T1-T10 only numerically corresponding vertebra. o The spinous processes are long and The anterior attachment of the ribs vary: slant inferiorly. Ribs 1 – 7 o attach independently to the sternum. Ribs 8 – 10 o attach to the costal cartilages superior to them. Ribs 11 – 12 o do not have an anterior attachment and end in the abdominal musculature. o Floating ribs Figure 47. Lateral view of a thoracic vertebrae. C. THORACIC SPINE ATYPICAL THORACIC VERTEBRAE the second vertebral column segment is possess whole facets. They display located between the cervical and lumbar variation in the size, location, and number vertebral segments. It consists of twelve of their superior and inferior costal facets. vertebrae, which are separated by intervertebral discs. T1 – Superior facet is not a demifacet o Along with the sternum and ribs, o This is the only vertebrae to the thoracic spine forms part of the articulate with the 1st rib. thoracic cage. T10 – A single pair of whole facets is present and articulates with the 10th rib. o These facets are located across both the vertebral body and the pedicle. T11 and T12 – Each have a single pair of entire costal facets located on the pedicles. Figure 46. Posterior aspect of Thoracic Spine Figure 48. Atypical Vertebra of Thoracic Spine THORACIC VERTEBRAE have four features which distinguish them from other vertebrae: o Vertebral body is heart shaped. BATCH 2028 1A 17 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024 UNIQUE LIGAMENTS. JOINTS AND ARTICULATIONS BETWEEN VERTEBRAL BODIES – adjacent vertebral bodies are joined by intervertebral discs, made of fibrocartilage. RADIATE LIGAMENT OF HEAD OF RIB This is a type of cartilaginous joint, known o Fans outwards from the head of as a symphysis. the rib to the bodies of the two BETWEEN VERTEBRAL ARCHES – vertebrae and intervertebral disc. formed by the articulation of superior and COSTOTRANSVERSE LIGAMENT inferior articular processes from adjacent o Connects the neck of the rib and vertebrae. the transverse process. The articulations between the vertebrae LATERAL COSTOTRANSVERSE and the ribs are unique to the thoracic LIGAMENT spine. For each rib, there are two separate o Extends from the transverse articulations: costovertebral and process to the tubercle of the rib. costotransverse. SUPERIOR COSTOTRANSVERE LIGAMENT o Passes from the upper border of the neck of the rib to the transverse process of the vertebra superior to it. Figure 51. A. Superior View of Thoracic Spine, B&C. Lateral view of Thoracic spine with articulations and ligaments Figure 49. Articulations between a rib and its numerically corresponding vertebrae. IV. PELVIS AND PERINEUM LIGAMENTS A. HIP BONE strengthened by the presence of numerous ligaments that is present throughout the The left and right hip bones (innominate, Vertebral Column pelvic bones) are two irregularly shaped o ANTERIOR AND POSTERIOR bones forming part of the pelvic girdle – the LONGITUDINAL LIGAMENTS bony structure that attaches the axial o Run the entire vertebral column skeleton to the lower limbs. length, covering vertebral bodies and IV discs. o LIGAMENTUM FLAVUM o Connects laminae of adjacent vertebrae. o INTERSPINOUS LIGAMENT o Connects spinous processes of adjacent vertebrae. o SUPRASPINOUS LIGAMENT o Connects the tips of adjacent spinous processes. Figure 52. Overview of the anatomical position of the hip bones ARTICULATIONS Sacroiliac joint o articulation with the sacrum Figure 50. Ligaments of the lumbar vertebrae Pubic symphysis BATCH 2028 1A 18 ANATOMY: HEAD AND NECK, THORAX, PELVIS AND PERINEUM DR BUNDAL, L.O 08/28/2024. ILIUM ISCHIUM o articulation between the left and Widest and largest of the three parts of the right hip bones hip bone, and is located superiorly. Hip joint 2 surfaces: o Articulation with the head of the o Inner surface – concave shape, femur which produces the iliac fossa; site of origin of the iliac muscle o External surface – convex shape; provides attachments to the gluteal muscles superior margin of the iliac wing: iliac crest o it extends from the anterior superior iliac spine (ASIS)