Upper Extremity Bones- Asynch 5

Anatomy of the Ulna and Carpals

• Trochlear notch is bordered by the olecranon and coronoid processes of the ulna.
• The rounded concavity on the lateral side of the coronoid process is the radial notch.
• The prominent ridge on the lateral surface of the ulnar shaft is known as the lateral border.
• The concavity between the supinator crest and distal part of the coronoid process is called the supinator fossa.

Carpal Bones

• The largest carpal bone in the proximal row is the scaphoid.
• The carpal tunnel is formed by the flexor retinaculum, converting the carpal arch.
• The carpal tunnel allows passage for 9 tendons and the median nerve.
• All fingers have three phalanges, however, the thumb has only two.

Bones and Features of the Upper Limb

• Each digit is composed of three bones: proximal phalanx, middle phalanx, and distal phalanx.
• The hook-like structure on the palmar surface of the hamate bone is called the hamulus.
• The scapula covers the posterolateral aspect of the thorax, overlying the 2nd to 7th ribs.
• The clavicle features a prominent conoid tubercle near its acromial end, close to the trapezoid line.

Muscle Attachments and Bone Structures

• The subclavian muscle attaches to the clavicle.
• The humerus has a lateral lip and a medial lip associated with the intertubercular sulcus.
• The humerus also features a radial groove on its posterior surface.
• The deltoid muscle attaches at the deltoid tuberosity located laterally on the humerus body.

Joint Articulations

• The head of the radius articulates with the capitulum of the humerus.
• The shape of the clavicle is S-shaped (also described as a double curve).
• The medial end of the clavicle is directed toward the scapula.

Skeleton Composition

• The axial skeleton includes the skull, vertebral column, and rib cage.
• The appendicular skeleton consists of bones of the limbs and girdles.
• The upper limb is comprised of the humerus, radius, ulna, carpals, metacarpals, and phalanges.
• The pelvic girdle is made up of the two hip bones (ossa coxae) and sacrum.
• The shoulder girdle is formed by the clavicle and scapula.

Additional Bone Features

• The conoid tubercle is located near the acromial end of the clavicle.
• The ulnar notch is found at the distal end of the ulna.
• The tuberosity of the ulna is situated superiorly toward the elbow.
• The rounded concavity on the lateral side of the coronoid process serves as a surface for radius articulation.

Joints and Fractures

• A joint lacking at least two degrees of freedom cannot perform circumduction.
• The radiocarpal joint is also termed the wrist joint.
• The scaphoid is notably the largest and most commonly fractured carpal bone.
• The median nerve passes through the carpal tunnel, alongside the tendon structures.