Anatomy Quiz: Upper Limb Bones

Axial Skeleton

• Colored beige on diagrams
• Forms the central axis of the body
• Includes the skull, vertebrae, sternum, ribs, sacrum, and hyoid

Appendicular Skeleton

• Colored green on diagrams
• Includes the pectoral girdle, upper extremity, pelvic girdle, and lower extremity

Bones of the Skeletal System

• 206 bones in a typical adult skeleton
• Number varies with development of sesamoid bones (like the patella)
• Number also varies with the presence of sutural (wormian) bones in the skull
• 270 bones at birth, but this number decreases with fusion

Anatomical Features of Bones

• Bone markings have ridges, spines, bumps, depressions, canals, pores, slits, cavities, and articular surfaces.
• Articulated skeletons held together by supports, showing the spatial relationships between bones.
• Disarticulated bones show surface features in detail.

Skull

• Most complex part of the skeleton
• Consists of 22 bones joined by sutures (immovable joints)
• Contains several cavities like the cranial cavity (brain case), orbits (eye sockets), nasal cavity, oral (buccal) cavity, middle- and inner-ear cavities, and paranasal sinuses
• Paranasal sinuses (frontal, sphenoid, ethmoid, maxillary) are air-filled, lined with mucous membranes, and add resonance to the voice while lightening the skull.

Cranial Bones

• Meninges (membranes) separate the brain from the bones.
• Dura mater is the thickest membrane.
• Arachnoid and Pia mater are other layers.
• Calvaria (skullcap) and cranial base are the two sections of the cranium.
• The base of the cranium has three basins—anterior, middle, and posterior.
• 8 cranial bones: frontal, 2 parietal, 2 temporal, 1 occipital, 1 sphenoid, 1 ethmoid.

The Frontal Bone

• Forms the forehead and part of the roof of the cranium.
• Features include the coronal suture, supraorbital margin, supraorbital foramen, and glabella.
• Contains the frontal sinus.

The Parietal Bones

• Form most of the cranial roof and part of the lateral walls.
• Bordered by the sagittal, coronal, lambdoid, and squamous sutures.
• Features include temporal lines for the temporalis muscle attachments.

The Temporal Bones

• Form part of the lateral wall and part of the floor of the cranial cavity.
• Consists of four parts: squamous, tympanic, mastoid, and petrous.
• Includes features like the zygomatic process, mandibular fossa, external auditory meatus, styloid process, mastoid process, mastoid notch, mastoid foramen, and stylomastoid foramen.
• Petrous part of the temporal bone separates the middle cranial fossa from the posterior cranial fossa.

The Occipital Bone

• Forms the rear and base of the skull.
• Contains the foramen magnum (opening for spinal cord), basilar part, occipital condyles, and condylar canal (not found in all people).
• Features include the external occipital protuberance and nuchal lines.

The Sphenoid Bone

• A complex bone forming part of the base of the skull.
• Features include the body, greater wing, lesser wing, optic canal, superior orbital fissure, sella turcica
• Includes foramina like foramen rotundum, foramen ovale, foramen lacerum, posterior nasal apertures or choanae, medial and lateral pterygoid plates, and the sphenoid sinus.

The Ethmoid Bone

• Located between the eyes, it contributes to the medial wall of the orbit as well as the walls and roof of the nasal cavity.
• Features include the cribriform plate, crista galli, superior nasal concha, middle nasal concha, perpendicular plate, and ethmoidal cells.

Facial Bones

• 14 bones anterior to the cranial cavity, supporting the teeth, the cheeks, and giving structure to the face. These include the maxillae, nasal bones, palatine bones, zygomatic bones, lacrimal bones, inferior nasal conchae, vomer, and mandible.

The Maxillae

• Largest facial bones and form the upper jaw.
• Features include alveolar processes with alveoli (tooth sockets), the cleft palate structure, the infraorbital foramen, and the inferior orbital fissure.
• Contains the maxillary sinus.

The Palatine Bones

• L-shaped bones forming the posterior portion of the hard palate, part of the lateral nasal cavity wall, and part of the orbital floor.
• Includes the greater palatine foramina.

The Zygomatic Bones

• Form angles of the cheekbones and part of the lateral orbital wall.
• Includes the zygomaticofacial foramen and zygomatic arch.

The Lacrimal Bones

• Smallest bones of the skull, forming part of the medial wall of each orbit.
• Contains the lacrimal fossa that houses the lacrimal sac and tears drain into the nasal cavity.

The Nasal Bones

• Form the bridge of the nose.
• Supporting cartilages shape the portion below the bridge area.

The Inferior Nasal Conchae

• The largest of the nasal conchae, located within the nasal cavity.
• They are separate from the other conchae which are components of the ethmoid bone.

The Vomer

• Forms the inferior portion of the nasal septum, supporting the nasal cartilages.

The Mandible

• Strongest bone of the skull, supporting the lower teeth.
• Includes the alveolus processes, mental symphysis, mental protuberance, mental foramen, and mandibular foramen.

Bones Associated With The Skull

• Includes the auditory ossicles (malleus, incus, and stapes) and the hyoid bone.
• The auditory ossicles are located within the middle ear cavity.
• The hyoid bone is a slender, U-shaped bone suspended from the styloid process of the skull, located between the chin and larynx.

The Skull In Infancy And Childhood

• Features structures such as fontanels, which are spaces between unfused cranial bones that contain a fibrous membrane and allow the skull to shift during birth and growth.
• Fontanels include the anterior, posterior, sphenoid (anterolateral), and mastoid (posterolateral) fontanels.
• The frontal bones fuse by age 6 (metopic suture).

The Vertebral Column And Thoracic Cage

• Composed of 33 vertebrae with intervertebral discs in most areas.
• Describes general features of a typical vertebra and special features of vertebrae in different regions such as cervical, thoracic, lumbar, sacral, and coccygeal.
• Anatomy and relationships of the ribs, sternum, and their articulation with the thoracic vertebrae are described.

The Cervical Vertebrae

• Describes unique features of C1 (atlas) and C2 (axis) vertebrae, including the location of the dens, transverse foramen, articular facets.
• Describes the anatomy of the other cervical vertebrae (C3-C7).

The Thoracic Vertebrae

• Discusses the 12 thoracic vertebrae and their articulation with the ribs, having larger bodies than cervical vertebrae but smaller than lumber vertebrae.
• Includes superior and inferior costal facets and their significance for rib attachments.

The Lumbar Vertebrae

• Includes the 5 lumbar vertebrae.
• Describes characteristics like thick, stout bodies, blunt, squarish spinous processes, and the superior articular processes facing medially.
• A discussion on their anatomical features including the vertebral foramen, spinous process, articular processes and lamina is included.

The Sacrum

• Composed of 5 fused sacral vertebrae.
• The anterior surface is smooth and concave and includes four transverse lines, showing regions of fusion.
• Include large anterior sacral (pelvic) foramina, sacral canal, and sacral hiatus.
• The auricular surface is a part of the sacroiliac joint and articulates with the hip bone’s superior articular processes.
• Alae, a pair of large wing like extensions, are located lateral to the superior articular processes.

The Coccyx

• Consists of 3-5 fused coccygeal vertebrae.
• Has a triangular shape.
• Has a pair of horns found on Co1 which are points of attachment for ligaments connecting the coccyx to the sacrum.

The Intervertebral Discs

• Discs support the weight of the body, and absorb shock.
• Structure includes the nucleus pulposus and annulus fibrosus.
• Note that herniated discs can cause painful pressure on spinal nerves.

The Pectoral Girdle And Upper Limb

• Describes the clavicle, scapula, humerus, radius, ulna, and wrist and hand bones.
• Includes features of the pectoral girdle's bones.
• Describes Articulations including sternoclavicular, acromioclavicular, and glenohumeral joints.

The Clavicle

• Clavicle is an s-shaped bone, similar in appearance to a small elongated “collar bone”, found in the superior portion of the thorax.
• Features include an acromial end (point where it attached to the shoulder), sternal end (flattened area where it connects to the sternum), and the conoid tubercle (a bumpy region).

The Scapula

• triangular plate located posteriorly over ribs 2 to 7.
• Features include the three sides (superior, medial, lateral borders), three angles (superior, inferior, lateral angles).
• Structures such as the suprascapular notch, spine, supraspinous fossa, and infraspinous fossa are present.
• Lateral features include the acromion, coracoid process, and glenoid cavity.

The Humerus

• The large bone of the brachium (upper arm).
• Features include the proximal head (hemispherical), anatomical neck, greater and lesser tubercles, deltoid tuberosity, intertubercular sulcus (groove), surgical neck, coronoid fossa, radial fossa, lateral and medial epicondyles.
• Distal end includes capitulum, trochlea, coronoid fossa, radial fossa, olecranon fossa, lateral and medial supracondylar ridges and epicondyles.

The Radius

• One of the two forearm bones.
• Features include the head, neck, radial tuberosity, radial notch, styloid process, and interosseous borders.

The Ulna

• One of the two forearm bones.
• Features include the trochlear notch, olecranon, coronoid process, radial notch, styloid process, and the interosseous membrane.

The Carpal Bones

• Eight bones form the wrist.
• The two rows are proximal (scaphoid, lunate, triquetrum, and pisiform) and distal (trapezium, trapezoid, capitate, and hamate).
• The pisiform is classified as a sesamoid bone, developed within the tendon of flexor carpi ulnaris muscle.

The Metacarpal Bones and Phalanges

• Metacarpals are bones of the palm.
• Phalanges are bones of the fingers.
• The thumb or pollex has two phalanges(proximal, distal).
• Other fingers have three phalanges each (proximal, middle, distal).

The Pelvic Girdle And Lower Limb

• Anatomical features of the pelvic girdle (coxal bones), femur, patella, tibia, fibula, and foot bones.
• Compares the male and female pelvic girdles and discusses functional significance of the differences.

The Femur

• The longest and strongest bone of the body.
• Features include the head, neck, greater and lesser trochanters, intertrochanteric crest, linea aspera, medial and lateral condyles, intercondylar fossa and the patellar and popliteal surfaces.

The Patella

• A specialized sesamoid bone within the tendon of the quadriceps femoris muscle.
• Has a superior base, a pointed inferior apex and articular facets on the posterior surface.
• The patella also has attachments to the superior aspect of the tibia through the patellar ligament.

The Tibia

• The medial leg bone that carries the weight of the body.
• Features include the medial and lateral condyles, intercondylar eminence, tibial tuberosity, and the anterior border.
• Tibial malleolus, a bony knob, is found on the inside part of the ankle.

The Fibula

• The lateral leg bone.
• Not weight-bearing, it helps stabilize the ankle.
• It assists the ankle with stability and has a lateral malleolus (found on the outside of the ankle).

The Ankle And Foot

• Carpal/tarsal bones form the ankle and foot.
• Features of the ankle and foot, including the talus, calcaneus, navicular, medial, intermediate, and lateral cuneiforms and cuboid bones.
• Discusses the arrangement of metatarsal and phalangeal bones within the foot.
• Discusses the three arches that help the foot absorb stress: medial longitudinal, lateral longitudinal, and transverse arches.
• Discusses pes planus (flat feet).

Test your knowledge about the bones of the upper limb in this anatomy quiz. Specifically, focus on the brachium, antebrachium, and wrist. Understand how these bones articulate and their functions within the skeletal system.