Upper Limb Anatomy Overview

General Overview

• The upper limb is comprised of the shoulder, arm, forearm, and hand.
• It's responsible for various functions, including reaching, grasping, and manipulating objects.
• It's structured for both strength and mobility.

Shoulder Girdle

• The shoulder girdle connects the upper limb to the axial skeleton.
• It consists of the scapula (shoulder blade) and clavicle (collarbone).
• The scapula is a flat, triangular bone that articulates with the humerus and clavicle.
• The clavicle acts as a strut, providing stability and support to the shoulder.
• Glenoid cavity: A shallow socket on the scapula that articulates with the head of the humerus. This shallow socket allows for a large range of movement but also increases susceptibility to dislocation.

Arm

• The arm is the region between the shoulder and elbow.
• It's primarily composed of the humerus, a long bone extending from the shoulder to the elbow.
• The humerus head articulates with the glenoid cavity of the scapula.
• Important bony landmarks include the greater and lesser tubercles, the deltoid tuberosity, and the anatomical neck.
• Medially located is the anatomical coronoid process of the humerus.

Elbow Joint

• The elbow joint connects the arm to the forearm.
• It's a hinge joint formed by the articulation of the humerus, radius, and ulna.
• The trochlea and capitulum of the humerus articulate with the corresponding parts of the radius and ulna.

Forearm

• The forearm comprises the radius and ulna.
• The radius and ulna are parallel bones that articulate at both ends.
• The radius runs laterally and the ulna runs medially.
• The radius and ulna allow for rotation and flexion of the forearm.

Wrist and Hand

• The wrist is formed by eight carpal bones arranged in two rows.
• These bones articulate with the radius and ulna.
• The wrist allows for flexion, extension, and side-to-side movement.
• The hand contains five metacarpal bones that articulate with the carpal bones.
• The fingers (digits) and thumb are made up of phalanges (finger bones.)
• The thumb (pollex) is a unique digit.

Muscles of the Upper Limb

• Numerous muscles are involved in the movement and support of the upper limb. The muscles work together to allow flexion, extension, abduction, and adduction.
• Muscles of the shoulder girdle are responsible for stabilizing the shoulder complex.
• Muscles of the arm, forearm, wrist, and hand control movements of the joint and individual digits.

Nerves and Vessels

• Nerves supply sensory and motor information to the upper limb.
• Major nerves include the axillary, musculocutaneous, radial, median, and ulnar nerves.
• Blood vessels supply oxygen and nutrients to tissues throughout the upper limb.
• Arteries such as the subclavian, axillary and brachial arteries are important components of the vascular system of the upper limb.

Articulations of the Upper Limb

• Articulations are the joints where bones meet.
• The shoulder joint (glenohumeral joint) connects the humerus to the scapula.
• The elbow joint connects the humerus to the radius and ulna.
• The wrist joint connects the radius and ulna to the carpal bones.
• The hand has complex articulations for finger movement and prehension.

Clinical Considerations

• Injuries to the upper limb are common, affecting various tissues.
• Fractures, dislocations, sprains, tendinitis, and nerve damage are potential issues.
• Medical imaging (X-rays, MRI, etc.) is critical in evaluating injuries.
• Physical therapy is often needed for recovery from upper limb injuries.