Intro to Anatomy, Head and Neck Region.pdf

1|ANALEC Merida, MVC 1PTA Anatomical Position Medial Standard reference position o used to indicate that a structure is nearer median Body is upright...

1|ANALEC Merida, MVC 1PTA Anatomical Position Medial Standard reference position o used to indicate that a structure is nearer median Body is upright plane; toward midline Feet together o Example: heart is more medial than the arms Face looking forward Lateral Mouth close and facial expression neutral o terms that indicate that the structure is farther Eyes open focused on something in the distance away the median plane; away from Midline Arms at side, Palms of hand forward, pad of thumb o Example: arms is more lateral than heart turned 90° Posterior/ dorsal o Functional position - palms are facing forward o denotes back surface *resting position - palms are facing the body o Toward the back Anterior/ ventral Anatomical planes o denotes nearer to front Sagittal Planes o towards the front o Median sagittal plane - vertical plane passing HANDS through the center of the body dividing it to equal o Palmar - anterior of the hand; palms right and left halves o dorsal surface - posterior of hand; back of the o Sagittal plane - vertical planes parallel to the palms median plane; divides body to right and left side FOOT Coronal plane (Frontal) o Plantar - sole of foot o vertical plane passing through the body at right o Dorsal - upper (top) surface angles to the median plane Proximal o dividing body to anterior (front) and posterior o Wrist, ankle (back) portions Distal Horizontal o Fingers, toes o planes passing the body at right angle to the Denote level in reference to upper or lower ends of body median and coronal planes o Inferior/Caudal - nearer to feet/tail o dividing the body into superior (upper) and o Superior/Cranial/ Cephalic - nearer to inferior (lower) parts. head/vertex/cranium o Transverse plane - lies perpendicular to the long Position relative to the core or root or attached end axis of a given structure o Proximal - nearer the trunk/core or point of origin ▪ In the leg, horizontal and transverse planes ▪ Shoulders are more proximal than the are the same because they pass through hands the long axis of leg or tibia o Distal - farther from trunk or point of origin ▪ in the foot, the horizontal plane remains Describes location relative to the center of a structure or the same as the leg, it divides the foot into space dorsal and plantar o Internal – location is inside the structure; inner while for transverse plane, it divides ear the foot into anterior and posterior o External – location is outside the structure; parts auricle, Helix Terms of Relationship and Comparison EXAMPLES: SUPERFICIAL, INTERMEDIATE, DEEP - terms used in o Head in relation to shoulder dissection to describe the position of one structure with ▪ The head is more medial and the shoulder respect to other structures is more lateral o Superficial - near to surface ▪ the head is more superior and the shoulder ▪ Epidermis is more inferior o Intermediate - between a superficial and deep o Position of thumb in the hand structure ▪ the thumb is lateral to the hand ▪ Dermis o Liver in relation to diaphragm o Deep - farther from surface ▪ liver is inferior to the diaphragm ▪ subcutaneous o Position of hip in relation to the lower extremity ▪ the hip is proximal than the lower extremity 2|ANALEC Merida, MVC 1PTA ▪ the hip is more superior than the lower o THUMB MOVEMENT extremity ▪ Abduction - Form a letter L with the thumb o Position of kidney in relation to abdominal cavity pointing forward ▪ Kidney is more dorsal or posterior ▪ Adduction - thumb is in front of index finger o Sternum in relation to the heart CORONAL PLANE ▪ the sternum is superficial than the heart o Abduction - away from the median plane in ▪ the sternum is anterior to the heart coronal plane o Adduction - toward the median plane in the coronal plane Terms of Laterality o THUMB MOVEMENT UNILATERAL ▪ Flexion - Form a number 4 o structures on one side only ▪ Extension - Form a number 5 o Heart, bladder HORIZONTAL PLANE BILATERAL o Rotation - turning or revolving a part of the body o structures having right and left members around its longitudinal axis o kidneys, lungs ▪ Medial rotation (internal) brings the IPSILATERAL anterior surface of a limb closer to the o occurring on the same side of the body median plane o Example: ipsilateral weakness of the right upper ▪ Lateral rotation (external) bring the and lower extremities anterior surface away from median plane CONTRALATERAL Usually used for shoulder or hip o occurring on the opposite side of the body joint; semi circle movement o Example: lesion is on one side and the effect was o Circumduction - a circular movement on the other side ▪ a combination of flexion, extension, o Stroke: left brain was affected, right limbs abduction and adduction occurring in such become weak a way that the distal end of the part moves ▪ contralateral weakness of the right upper in a circle and lower extremities o Opposition - movement by which the pad of the first digit (thumb) is brought to another digit Terms of Movement o Protraction - anterior movement of shoulder SAGITTAL PLANE - Bend forward, moving towards the ▪ move the shoulder forward plane o Retraction - posterior movement of shoulder o Flexion - decreasing the angle between the bone ▪ move the shoulder backward or parts of the body ▪ Older definition: Putting 2 ventral surfaces o Protrusion - movement anteriorly (forward); used together - it is confusing because the terms for mandible ventral and dorsal are commonly used in o Retrusion - is a movement posteriorly animals and it's not always the same for (backward); used for jaw or mandible humans o Extension - increasing the angle between the o Elevation - raises or moves a part superiorly bones and parts of the body ▪ used in scapula ▪ opposition of Flexion o Depression - lowers of moves a part inferiorly o Hyperextension - extension beyond the normal ▪ used in scapula limit o FOOT o Eversion - moves the sole of foot away from the ▪ dorsiflexion - flexion at the ankle joint/ median plane (turning sole laterally) flexion of ankle o Inversion - moves the sole of foot toward the going upward median plane (turning sole medially) sometimes called extension ▪ plantarflexion - turns foot toward plantar o Pronation - movement of forearm and hand that surface/ extension of ankle rotates the radius medially around its Going downward longitudinal axis sometimes called flexion 3|ANALEC Merida, MVC 1PTA ▪ palm faces posteriorly and dorsum faces Sebaceous glands anteriorly o Secrete sebum o Supination - movement of forearm and hand that o attached to the hair shaft and is the one who gives rotates the radius laterally around its you the oil and preserves the flexibility of the hair longitudinal axis o it also preserves the surface of the epidermis ▪ dorsum of the hand faces posteriorly and Sweat glands palm faces anteriorly o coiled spiral tubular glands that are found the best in the skin SKIN o found all over the body except Divided into two parts: Superficial (Epidermis) and deep ▪ Lips, nailbed, glans penis, clitoris (dermis) Epidermis Fascia o Stratified epithelium connecting varying amounts of fat o Thick over palms of soles and feet Functions: ▪ Flat and when they mature, they are raised o Separates, supports and interconnect organs and to the surface and slough off structures Dermis o Allows movement of one structure relative to o Thicker another o Composed of dense connective tissue containing o Transit of vessel and nerves blood vessels, lymphatic vessels and nerve 2 types: o Thickness varies in different parts of body o Superficial (subcutaneous) ▪ usually it is thinner in the anterior o Deep compared to the posterior Superficial (subcutaneous) ▪ usually is thinner in women o Mixture of loose areolar and adipose tissue ▪ Connected to the underlying deep fascia or uniting the dermis to the underlying deep fascia bone by a superficial fascia which is known Deep fascia as subcutaneous tissue o muscular, visceral etc *skin creases are usually seen in the areas of the joint ▪ muscular fascia - If it covers the muscles o describe a skin over joints that are folded and are ▪ visceral fascia - if it covers the organs firmly tethered together o Membranous layer investing in deeper structures o gives ability to the joints to move o Function depending on the location ▪ In thorax and abdomen - Thin film of Skin appendages areolar tissue covering muscles and Nails - keratinized plates on dorsal surfaces of tips of aponeurosis fingers and toes ▪ In limb form sheath around muscles to hold o Root - attached to finger; proximal end of the nail them in place o free edge - distal end is usually loose ▪ May divide deep muscles into o nail fold - surrounded by overlapped skin compartments Hair and hair follicles - grows out from the follicle and is ▪ In joints form restraining bands called usually found deep in the dermis and usually start at the retinacula and hold tendons in position or hair bulb serve as pulley around tendon o bulbs - penetrate deep part of the dermis Superficial Deep ▪ concave at the end (Subcutaneous) o hair papilla - Vascular connective tissues which Just beneath dermis Deep, organized occupy the hair bulbs o Arrector pilli - smooth muscle attached to the connective tissue ends of the hair; Connects to the hair follicle Made up of loose Outer layer is attached ▪ when does arrector pilli contracts? connective tissue to deep surface of it pulls and raises the hair like when containing large amount superficial fascia; you have goosebumps of fat inward extensions form o hair is distributed all throughout the body but intermuscular septa that there are certain areas that do not have hair compartmentalize ▪ Palms, lips, glans penis, clitoris, labia groups of muscle minora and majora 4|ANALEC Merida, MVC 1PTA Thickness varies Surrounds individual o Have striations but are involuntarily controlled muscle And are controlled by the autonomic nervous system Allows movement of the Separate lining of o They are arranged in swirls and spirals skin over deeper areas abdominal cavity from o They are the ones that form our myocardium Or of the body and passage fascia covering surface the muscles of our heart of vessels and nerve, and of muscle o They are stimulated by their own conducting source of energy (fat) system Which is the conducting system of the Extraperitoneal fascia/ heart endothoracic fascia o They are supplied by the autonomic nervous Loose areolar Made of membranous fibers and they terminate in the nodes of the conducting system in its myocardium Muscle Skeletal Muscle Tissue Functions: Name is based on its location (attached to the bones of o Produces movement the skeleton) o Gives form to the body Striated – contains alternating light and dark bands o Provides heat visible under a light microscope Types Muscles are voluntary because it can be made to o Skeletal Muscle contract or relax by conscious control Single muscle o Cardiac Muscle fiber is long, cylindrical in shape and has many nuclei at o Smooth Muscle the periphery of cells Skeletal Individual muscle fibers are arranged parallel to each o Most abundant other o voluntarily controlled o Most of the skeletal muscles are the ones Smooth responsible to move our joints That's why they o long spindle shaped cells have attachments to the bone o closely arranged in bundles or sheets o They are also called voluntary muscles o controlled by autonomic nervous system ▪ We can contract or relax it consciously o Lines the organs Striated muscle o when they contract, they can cause a wavelike o Skeletal Muscle (Striated or Voluntary muscle) contraction Because they are arranged in a attached to the skeleton and fascia of limbs, body circular manner, it is like they are milking the wall and head/neck large, strong and unbranched structure that is found on the lumen with transverse striations stimulated by voluntary ▪ Peristalsis - movement in the GI tract or reflex by the somatic nervous system o for bladder or uterus, The muscle fibers are o Each striated muscle has 2 or more attachments arranged in an irregular fashion, and when they o PARTS contract, the contraction is usually slow and ▪ Origin – attachment that moves the least sustained and this will help in the expulsion of the Example: biceps means it has two content of the organs origins: The coracoid process (short o they also line our blood vessels, they are also head) and the superior glenoid fossa arranged in a circular fashion and they can either ( long head) increase or decrease the diameter of the lumen ▪ Insertion – attachment that moves the that they line most o Depending on the organs, they are stimulated by The insertion is at the radius the contractions of local ___ fibers or from a ▪ Belly – the fleshy part of muscle nerve impulse that comes from the autonomic The two bellies of the biceps will both nervous system or the contraction could be insert at the radius stimulated by hormones ▪ Tendon – ends of muscles attached to bone Cardiac ▪ Aponeurosis – flattened muscles attached o Specialized striated muscles by thin strong sheet of fibrous tissue Which o They have the characteristic of smooth and are usually part of the deep fascia striated ▪ Raphe – interdigitation of the tendinous ends of fiber 5|ANALEC Merida, MVC 1PTA o TYPES BASED ON SHAPE SKELETAL SYSTEM ▪ flat muscle - parallel fibers with an Bone aponeurosis (external oblique) a highly specialized, hard form of connective tissue that ▪ pennate muscle - featherlike in the forms most of the skeleton and is the chief supporting arrangement of their fascicle (deltoid) tissue of the body Bipennate (2 sides), unipennate (1 o They are living tissues and are composed of cells, side) or multipennate (like hair; fibers, and matrix deltoid) o Bones are hard because of the calcification of its ▪ fusiform - spindle shape (biceps brachii) extracellular matrix ▪ quadrate - has four equal sides (pronator o They're also elastic and that's why they don't quadratus) break easily Can be rectangular or square ▪ The degree of elasticity is because of the ▪ circular or sphincteral - surrounds orifice presence of organic fibers (orbicularis oris) Functions: Sphincteric o protection of vital structures Orbicularis occuli (eyes) ▪ Skull for the brain, rib cage for the thoracic o CLASSIFICATION BASED ON MOVEMENT part ▪ Prime movers or agonist - main muscle that o support for the body mechanical basis for activate a specific movement of the body; movement contract actively to produce the desired o storage for salts (e.g. calcium) movement o continuous supply of new blood cells Biceps Brachii - Goal of movement is ▪ In the bone marrow elbow flexion Cartilage ▪ Antagonist - muscles that oppose the action resilient, semirigid form of connective tissue of prime mover Avascular - has no blood vessels, lymphatics or nerves, Triceps - usually relaxed when the nutrition is by diffusion biceps are contracted; Its movement Functions: is elbow extension o Support soft tissues ▪ Synergist - prevent the intervening joint o Provide smooth, gliding surface for bone movement when a prime mover passes articulation & joints over more o Enable development and growth of long bone They act similarly as agonist Types: Brachioradialis - Helps flex the elbow o Hyaline Brachialis o Elastic ▪ Fixator - stabilizes the origin of prime mover o Fibrocartilage so that the prime mover can act more efficiently Hyaline cartilage Sometimes the fixator and synergist o Most common, matrix has moderate amount of are the same Because they aid in the collagen fiber movement of the muscle o Plays an important part in growth the length of long bones ▪ Prime Mover: Biceps femoris, ▪ Located in the epiphyseal plates semimembranosus semitendinosus o Has great resistance to wear & tear and covers ▪ Synergists: popliteus, gastrocnemius, articular cartilage (end of bones in the joints) gracilis, sartorius o Incapable of repair ▪ Antagonists: Quadriceps - vastus lateralis, o Hyaline found as supportive tissues in the nose, vastus mediali, vastus intermedius, rectus ears, trachea, larynx, and smaller respiratory femoris tubes articular cartilage; reduces friction and acts ▪ Fixator: Careful balance between medial as shock absorbing tissue. and lateral stabilizers of the knee must be o Forms the costal cartilages where ribs attach to maintained to prevent excessive internal or the sternum and is the precursor to bone in most external rotation of the tibia. More of the embryonic skeleton complex relationships between synergistic pairs 6|ANALEC Merida, MVC 1PTA Fibrocartilage Flat bone o Matrix contains limited number of cells and o Composed of thin inner and outer layers of ground substance with substantial amount of compact bone called tables and separated by collagen fibers cancellous bone called diploe o Found between TMJ (tempomandibular joint), ▪ Skull, scapula sternoclavicular joint and knee fibrocartilage a Irregular bone good shock absorbing material in the pubic o Thin shell of compact bone with interior made of symphysis and intervertebral disks. cancellous bone ▪ They contain materials that are good for ▪ No specific/regular shape absorbing stress and shock ▪ Vertebra, pelvis o If damaged, it repairs itself slowly Sesamoid bone o Have poor blood supply in joint disc thus do not o Bone formed within a tendon where tendon repair themselves when damaged passes over a joint Elastic ▪ Patella - largest sesamoid bone; buried o matrix contains collagen with large number of within the muscle (quadriceps) elastic fibers o Buried in the tendon; its free surface is covered o Is very flexible with cartilage o Repairs itself with fibrous tissue o Reduces friction on the tendon; alter direction of o examples: epiglottis and cartilage of the ear pull of a tendon (external) lobes, pharyngotympanic (eustachian) tubes, epiglottis Two Types of Skeleton Axial Skeleton o bones of head, neck and trunk Bone has 2 Forms Appendicular Skeleton Compact bone or trabecular o bones of the limbs including those forming the o Solid mass pectoral and pelvic girdles Spongy or Cancellous bone o Consists of branching trabeculae that are Bone Surface Markings arranged to resist the stress and strains structural features adapted for specific functions Two major types: Classification of bones o Depressions and openings According to shape (5) ▪ Form joints or allow the passage of soft o Long bone tissues (vessels, nerves, etc) o short bone Usually seen at the end of joints o flat bone o Processes o irregular bone ▪ Projections or outgrowth that either help o sesamoid form joint or serve as attachment points for connective tissue Long bone o Found in limbs Markings and Features of Bones ▪ Humerus, radius/ulna, femur, tibia/fibula Processes that form joints o Length is greater than breadth o Condyle o Have tubular shaft (diaphysis) and epiphysis (end ▪ large, rounded articular area; found at end of the bone) of bones o Shaft contains marrow cavity with bone marrow o Facet ▪ Where red blood cells are produced ▪ smooth, flat area, usually covered with o Outer portion is composed of compact bone cartilage where a bone articulates with covered by periosteum another bone Short bone Processes that form attachment point for connective o Found in hands and feet tissue ▪ Carpals, tarsals o Crest o Cuboidal in shape ▪ ridge of bone o Composed of cancellous bone covered with thin o Epicondyle layer of compact bone ▪ eminence superior to a condyle 7|ANALEC Merida, MVC 1PTA o Line Classification of joints according to function/movement ▪ linear elevation o Synarthroses = no/little movement o Spinous process ▪ Ex: Sutures, Teeth, Epiphyseal plates, 1st rib ▪ projecting spine-like part and costal cart o Trochanter o Amphiarthroses = slight movement ▪ large blunt elevation ▪ Ex: Distal Tibia/fibula Intervertebral discs o Tubercle Pubic symphysis ▪ small raised eminence o Diarthroses = great movement o Tuberosity ▪ Glenohumeral joint Knee joint TMJ ▪ large rounded elevation Depression and openings o Fossa ▪ shallow depression o Fissure ▪ narrow slit between adjacent parts of bone through which blood vessels or nerve pass o Foramen ▪ passage/opening through which blood vessels, nerves or ligament pass o Meatus ▪ tubelike opening; ear canal Classification of Joints according to those separated by SUMMARY a cavity and without cavity o True Joints or Synovial joints Process – extension of a bone away from the bone’s surface. ▪ united by an articular cartilage (hyaline) Condyle – rounded eminence that articulates with a with a joint cavity enclosed by a joint depression or a fossa on another bone. capsule containing synovial fluid o False Joints or Solid joints Epicondyle – raised, rounded area located above a condyle. ▪ joints without articulating cavity, with no Trochanter – very large, roughened, raised area found capsule and no synovial fluid on the femur. The word "trochanter" is the Greek word for "a runner." A runner runs thanks to his or her femur. Components of SYNOVIAL JOINTS: (7) o Articular cartilage: hyaline; covers ends of both Tuberosity – similar to a trochanter but smaller. Crest – narrow ridge of bone. bones articulating o Synovial (joint) cavity: space holding synovial fluid Spine – sharp, slender projection o Articular capsule: Made of 2 layers Head – rounded, enlarged end of a long bone, Sits atop a narrow portion of the bone called the neck. ▪ Fibrous: external, dense CT for strength & Fossa – shallow depression that usually articulates with stabilize joint a condyle or head of another bone. Sometimes referred ▪ Synovial membrane: internal, produces to as cavities. synovial fluid o Synovial fluid: viscous; in capsule and articular Foramen (pl. foramina) – hole for passage of nerves, blood vessels, or the spinal cord. cartilages; prevent friction between two Meatus – canal-like passageway. articulate surfaces o Reinforcing ligaments: Facet - Smooth flat articular surface. Example: Superior Articular facet of vertebra. Forms parts of joints. extracapsular/intracapsular o Nerves + vessels: Highly innervated, Highly Ramus – arm-like bar of bone Line - narrow ridge or border. Example: linea aspera of vascular o articular disc (fibrocartilage): improves the fit of 2 femur. bones to increase stability; shock absorber JOINTS o Fat pads articulation or junction between two or more bones or parts of a skeleton May either have movement or none 8|ANALEC Merida, MVC 1PTA CONDYLOID JOINT - (ovoid);also known as ellipsoid (wrist joint); the convex oval shape projection of one bone fits into the oval shaped depression of another bone; allows flexion and extension; abduction and o adduction and circumduction; BIAXIAL o example: metacarpophalangeal joint o Types of True Joint/Synovial joint Based on shape of their articular surface o synovial joints are described as plane (flat), hinge (ginglymus), pivot, condylar (ellipsoid), saddle, PIVOT JOINTS (trochoid) - UNIAXIAL joint; articulation of ball and socket a rounded or pointed surface and partly by a ligament; Based on movement allows rotation o universal joint are described as uniaxial o example: atlanto-axial joint (cervical 1 and (movement in one plane), biaxial (movement in cervical 2 joint); superior radio-ulnar joint two planes) and multi-axial (movement in three (pronation and supination) planes) Types of Synovial/True Joint Based on Shape o PLANE JOINTS - (Irregular); opposed surfaces of bones are flat; permits gliding or sliding movements; UNIAXIAL o examples: acromioclavicular joints, intercarpal, intertarsal, sternoclavicular BALL AND SOCKET (universal, spheroidal, enarthrodial) - joint allowing the following movements: flexion/extension, abduction/adduction, rotation and circumduction; MULTIAXIAL o o example: hip and shoulder joint HINGE JOINTS (ginglymus) - one plane joint which o permits flexion and extension movements only; UNIAXIAL o example - elbow, knee, ankle and interphalangeal UNIAXIAL BIAXIAL MULTIAXIAL o Plane Condyloid Ball and Socket Hinge Saddle SADDLE JOINT - are joints with opposing surfaces Pivot shaped like a saddle; allows flexion/extension, abduction/adduction and opposition; MULTIAXIAL Stability of the joint depends on: o example: carpometacarpal joint of the thumb 1. articular surface o Stable joints: hip, ankle o Unstable joint: knee, acromioclavicular ▪ Tibia and femur are just like on top of each o other 2. Ligaments - usually stabilizes the joint o Fibrous ligaments o Elastic ligaments 9|ANALEC Merida, MVC 1PTA Solid Joints (false joint) o Special senses are within the skull bones and o Connection between skeletal elements where cavities adjacent surfaces are linked together either by ▪ Smell, vision, taste, hearing fibrous connective tissue or by cartilage o Digestive and respiratory systems begin in this (fibrocartilage) region Types of Solid or False Joints ▪ NOSE LARYNX TRAHEA, MOUTH PHARYNX o Fibrous joint (Sutures) - joined by fibrous tissue esophagus ▪ examples: sutures of the skull (parietal o Contains endocrine organs suture - connects parietal bone), ▪ Located at head and neck syndesmoses (e.i. Interosseous membrane ▪ Parathyroid gland of forearm; between radius and ulna), gomphosis or dentoalveolar syndesmosis Osteology (teeth and jaw) Skeleton of the head and neck includes the following: o Cartilaginous joints - are united by hyaline o skull cartilage or fibrocartilage o middle ear - ossicles: incus, malleus, stapes; the ▪ Primary (synchondrosis) - temporary three small bones unions as joints of epiphyseal plate; allows o hyoid bone - neck region growth in the length of the bone; where o cervical vertebrae - neck region two ossification enters in developing bone remain separated by a layer of cartilage Example: between first rib and manubrium, epiphyseal plate; between head and shaft of developing long bone ▪ Secondary (symphyses) - strong slightly movable joints united by fibrocartilage example intervertebral disc, symphysis pubis The Skull Cranium o Frontal bone (1) o Parietal bone (2) o Occipital bone (1) o Temporal bone (2) o Sphenoid bone (1) o Ethmoid bone (1) Facial Skeleton o Zygomatic bone (2) o Maxilla (2) HEAD AND NECK REGION o Nasal bone (2) Region of the body that contains important structures o Lacrimal bone (2) compressed into a small area o Vomer (1) Skull forms majority of the structure in the region o Palatine bone (2) Functions: ○ Houses the brain and meninges as well as o Inferior conchae (2) 12 pairs of cranial nerves o Mandible (1) 10 | A N A L E C M e r i d a , M V C 1 P T A Cranial skeleton ▪ Supraorbital margin o Mostly flat bone, and mostly single except for contains the supraorbital notch or parietal, temporal foramen for the passage of o Surrounds the brain supraorbital nerve and vessel o Divided into: ▪ Orbital margin ▪ skull vault (calvarium) bounded by frontal bone, zygomatic Mostly flat bone and maxilla (medial margin) upper part of cranium Boundaries: walls; frontal (superior), Forms root and side walls of cranial lateral - maxilla lacrimal ethmoid, cavity zygomatic, floor - zygomatic, maxilla Composed of flat bones (frontal, Margin - outer area parietal and occipital) forming the o Zygomatic bone external and internal tables of ▪ also known as cheek bone, zygoma, malar compact bone bone o Base – lower part of the cranium and forms floor ▪ articulates medially with maxilla, laterally of cranial cavity with zygomatic process of temporal bone Facial Skeleton ▪ Zygomaticofacial foramen pierces on o Mostly irregular and paired bones lateral side for passage of zygomaticofacial o Composed of irregular bones fused together and zygomaticotemporal nerve o Mandible –only movable part of the facial bone Sensory nerves o Nasal bone Anterior Aspect of Skull ▪ form the bridge of nose o Frontal bone ▪ nasal cavity is divided into 2 by nasal ▪ forms the forehead septum (cartilage) largely formed by vomer ▪ articulates with frontal process of the ▪ nasal conchae (superior and middle) are maxilla and nasal medially and laterally found on the lateral wall of each nasal with the zygomatic bones cavity ▪ Glabella is the slightly depressed area Superior and middle - cartilage between the supraciliary arch Inferior - bone o Maxilla ▪ form the upper jaw ▪ forms anterior part of hard palate, lateral wall of nasal cavities and floor of orbital cavities ▪ Intermaxillary suture (joint) is the midline of the 2 bones (the one with arrow) ▪ alveolar processes include sockets and ▪ Nasion constitute the supporting bone for intersection of frontal and nasal maxillary teeth bone; related to the depressed area ▪ maxillary sinus (bridge of the nose) pyramid shape cavity with mucous also articulates with the lacrimal, membrane; ethmoid and sphenoid bones communicates with nasal cavity; forms roof of orbit and floor of cranial acts as voice resonator cavity 11 | A N A L E C M e r i d a , M V C 1 P T A Symphysis menti - ridge on the midline surface of body of mandible Mental foramen – transmits inferior alveolar nerve and vessels Mental spine (genial tubercles) - origin of genioglossus muscle above and geniohyoid below Genioglossus - moves the tongue; Geniohyoid - inserts to the hyoid bone Mylohyoid line - where mylohyoid muscle originates Submandibular fossa – submandibular salivary gland ▪ Infraorbital foramen Sublingual fossa – sublingual gland for passage of infraorbital nerve and Alveolar part – for sockets of root of vessel teeth o Mandible Digastric fossa - found on the base, ▪ lower jaw for attachment of anterior bellies of ▪ consists of horizontal body and 2 vertical rami digastric; joined at the angle of the mandible Condyloid process (head) - insert into ▪ contains the mental foramen for passage of the socket of the skull; only mental nerve and vessel attachment of mandible to the skull ▪ alveolar process house the mandibular teeth Coronoid process ▪ symphysis menti Mandibular notch - between region where the halves of the fetal condyloid and coronoid process mandible fuse Mandibular foramen – inferior If not fused together - clef chin alveolar nerve Alveolar process of the mandible that houses the mandibular teeth ▪ When we were still infants, it just connected right before we were born ▪ Articulates with the skull at the temporomandibular joint Looks like a condyloid but snell refers to it as a modified hinge joint ▪ Parts: Body – horizontal plate, horseshoe shape Rami – vertical Angle –meeting of the body and rami 12 | A N A L E C M e r i d a , M V C 1 P T A Lateral Aspect of the Skull o Squamous part of occipital bone o Parietal bone o Greater wing of sphenoid ▪ form the sides and roof of the cranium and o Ramus and body of the mandible articulate each other through the sagittal o Temporal fossa suture ▪ located below the superior and inferior ▪ articulates with occipital bone at the temporal lines lambdoid suture and frontal bone at the o Infratemporal fossa coronal suture ▪ found below infratemporal crest on the greater wing of sphenoid. Pterygomaxillary fissure leads to pterygopalatine fossa o Temporal fossa ▪ bounded by the temporal line and zygomatic arch ▪ Pterion found 3 to 4 cm superior to the midpoint of zygomatic arch; H shape formation of sutures that unite the frontal, parietal, temporal and sphenoid bones; clinically important because it is the thinnest part in the lateral wall of skull under is the anterior division of middle meningeal artery and vein Can cause bleeding if damaged Posterior Aspect of the Skull o Occipital bone ▪ external occipital protuberance (inion) is a palpable elevation in median plane; ▪ serves as attachment of muscles and ligamentum nuchae ▪ superior nuchal line, inferior nuchal line ▪ extension of external occipital protuberance laterally toward temporal bone - lambdoid suture ▪ Lambda - intersection point of sagittal and lambdoid suture o External acoustic opening o Foramen Magnum - large opening in the base of ▪ entrance to external acoustic meatus which occipital bone leads to tympanic membrane ▪ Cerebral cortex cereberum brain stem - o Mastoid process of temporal bone midbrain pons medulla and spinal cord o Styloid process - pointed structure under the acoustic opening 13 | A N A L E C M e r i d a , M V C 1 P T A ▪ Tiny dots o Anterior fontanel - formed by sagittal suture and coronal suture ▪ Closes around 18 months; diamond in shape ▪ Becomes a bregma o Posterior fontanel - triangle in shape; formed by lambdoid and sagittal suture ▪ Close around the 1st year ▪ Becomes the lambda Base of Skull o Hard palate ▪ formed by palatine process of maxillae and horizontal plates of palatine bone posteriorly o Sphenoid bone ▪ irregular unpaired bone consisting of body, greater and lesser wings and pterygoid process o Foramen magnum ▪ for passage of spinal cord and its covering, the vertebral arteries, anterior and posterior spinal arteries, the accessory nerve o Occipital condyle ▪ by which skull articulates with vertebral column o Jugular foramen Superior Aspect of the Skull ▪ passage of internal jugular vein and CN IX o Oval shape through CN XI ' o Formed predominantly by the parietal bones All 11 cranial nerves innervate the o Broadens posterolaterally at parietal eminences skull, and comes from the brain; for o Coronal suture (frontal and parietal bones) vagus, it innervates lower o Sagittal suture (between parietal bones) o Internal acoustic meatus o Bregma ▪ for passage of CN VII - hearing and VIII - ▪ landmark formed by intersection of sagittal facial and coronal sutures o Carotid canal for passage of internal carotid o Vertex artery ▪ most superior point of skull o Stylomastoid foramen o Parietal foramen ▪ for transmitting the facial nerve and ▪ located posteriorly in parietal bone near stylomastoid artery sagittal suture for transmission of emissary veins 14 | A N A L E C M e r i d a , M V C 1 P T A o Middle Cranial Fossa ▪ Small median part and expanded laterally ▪ Formed by the sphenoid bone ▪ Lodges the temporal lobes of the cerebral hemisphere ▪ Most number of opening ▪ Boundaries: Internal Surface of the skull o divided into 3 cranial fossa Anteriorly lesser wing of sphenoid ▪ Anterior cranial fossa Posteriorly Between anterior and middle: lesser superior borders of the petrous wing of the sphenoid parts of temporal bones ▪ Middle cranial fossa Laterally Between anterior and middle: lesser squamous parts of temporal wing of the sphenoid bones, greater wing of Between middle and posterior: sphenoid and parietal bones petrous part of the temporal bone Floor ▪ Posterior cranial fossa greater wing Between middle and posterior: sphenoid and squamous and petrous part of the temporal bone petrous parts of the temporal o bone Anterior Cranial Fossa ▪ Parts/Openings ▪ shallowest Sphenoid bone ▪ Lodges frontal lobes of the cerebral body, greater and lesser wings, hemispheres sphenoid air sinuses ▪ Boundaries: Optic canal Anterior – inner surface of frontal bone optic nerve - CN2 and carotid Posterior – lesser wing of the sphenoid artery – ophthalmic artery ▪ Parts: Superior orbital fissure Ethmoid bone lacrimal, frontal, trochlear4, Crista galli oculomotor3, (CN3 4 6) foramen cecum - small hole above crista nasociliary, abducens6 nerves, galli superior ophthalmic vein Cribriform plate - where olfactory nerve- Foramen rotundum CN1 will pass through; small perforations maxillary nerve (V-2(branches) Anterior clinoid process - trigeminal; 2nd part of CN5) Groove for optic chiasm V1 - square orbital 15 | A N A L E C M e r i d a , M V C 1 P T A Foramen ovale mandibular nerve (V-3_ , lesser petrosal nerve Foramen spinosum middle meningeal artery Foramen lacerum small blood vessel Carotid canal internal carotid artery ▪ Sphenoid bone Butterfly shape with a centrally placed body that contains sphenoid air sinuses o Posterior Cranial Fossa Parts: ▪ Deep and lodges parts of hindbrain Greater and lesser wings (cerebellum, pons and medulla oblongata) Sulcus chiasmatis; optic chiasm ▪ Biggest Anterior and posterior clinoid ▪ Boundaries: process Superior Tuberculum sella border of the petrous part of Sella turcica (pituitary the temporal bone gland) Posterior Dorsum sellae (back internal surface of the part) squamous part of occipital bone Floor basilar condylar and squamous parts of occipital bone, mastoid process of temporal bone Roof fold of dura (tentorium cerebelli) ▪ Parts: Foramen magnum medulla oblongata (after exiting this, spinal cord) and surrounding meninges; ascending spinal parts of the spinal accessory nerve CN11, vertebral arteries Hypoglossal canal hypoglossal nerve Jugular foramen (from ant to post) inferior petrosal sinus, glossopharyngeal (CN IX), vagus (CN X) and spinal accessory nerves (CN XI), sigmoid sinus Internal acoustic meatus vestibulocochlear nerve (CV VIII) and the sensory and motor roots of facial nerve (CN VII) 16 | A N A L E C M e r i d a , M V C 1 P T A THE SCALP Consists of skin (normally hair bearing) and subcutaneous tissue, covering the calvaria, from superior nuchal lines on the occipital bone to the supraorbital margins on the frontal lobe. Laterally, extends to the temporal fascia to the zygomatic arches Consists of 5 layers of tissue: ▪ Skin contains: sweat and sebaceous glands hair follicles has abundant arterial supply and good venous and lymphatic drainage ▪ Connective tissue thick, dense, richly vascularized subcutaneous layer well supplied with cutaneous nerve ▪ Aponeurosis (epicranial aponeurosis) Where the muscle of the scalp is flat a strong thin, tendinous sheet that covers the calvaria between unites the occipital and frontal bellies of the MAJOR OPENINGS IN THE BASE OF THE SKULL AND occipitofrontalis muscle (epicranius STRUCTURES PASSING THROUGH THEM muscles) Subaponeurotic space below the epicranial aponeurosis; limited in the front and behind by origins of the occipitofrontalis muscle; attached laterally as far as temporal fascia Space after these 3 structures ▪ Loose areolar connective tissue occupies the subaponeurotic space that may distend with fluid resulting from injury or infection allows movement of the scalp proper over the underlying calvaria contains emissary veins connecting superficial veins of scalp with diploic veins Veins that go and enter the skull If have an infection, it can easily travel to skull and brain Most dangerous part so need to be careful 17 | A N A L E C M e r i d a , M V C 1 P T A ▪ Pericranium Covering for skull dense layer of connective tissue that forms the external periosteum of the calvaria; is attached but can be stripped fairly easily from calvaria Vascular supply of scalp o Arterial supply ▪ Comes from external carotid artery through the occipital, posterior auricular and superficial temporal arteries; and from internal carotid artery through the supratrochlear and supraorbital arteries External carotid - occipital Pulsations - superficial temporal Nerves - gives sensations o Venous supply ▪ drainage of superficial parts is through the accompanying veins of scalp arteries the supraorbital and supratrochlear veins Muscle of the Scalp o Occipitofrontalis muscle ▪ Origin : 4 bellies - 2 occipital and 2 frontal Meet at aponeurotic area Occipital belly – from nuchal lline Frontal belly – from skin and superficial fascia of eyebrows ▪ Nerve supply Facial nerve (cranial nerve 7) Suppl ymost of the muscle that support you face ▪ Action Raise eyebrows in expression of Clinical Notes surprise or horror o Scalp infection Sensory nerve supply of scalp ▪ Loose connective tissue layer is the danger o from anterior to the auricle – trigeminal nerve area of scalp because pus or blood spreads o posterior to the auricle – from spinal cutaneous easily in it nerve (C2-3) ▪ Infection in the areas may pass through the emissary veins and enter the cranial cavity o Laceration ▪ Most common type of head injury ▪ Because of the strength of the aponeurosis, superficial laceration in the skin do not gape because margins are held tightly in this layer