Chapter 10 (4)

• The upper limb is used for a broad range of actions such as climbing, grasping, throwing, writing, playing musical instruments, and manipulating small objects.
• Functional groupings of the muscles of the upper arm include; muscles that act on the scapula, muscles that act on the humerus and shoulder joint, muscles that act on the forearm and elbow joint, and muscles that act on the wrist, hand, and fingers.
• Muscles acting on the shoulder include the anterior group of muscles of the pectoral girdle, the pectoralis minor which is ribs 3 to 5 to the coracoid process of the scapula and draws scapula laterally, AND the serratus anterior which is all the ribs to the medial border of the scapula and draws the scapula laterally and forward and is the prime mover for reaching and pushing.
• The trapezius stabilizes the scapula and shoulder, as well as elevates and depresses the shoulder apex. The levator scapulae elevates the scapula and flexes the neck laterally. The rhomboid minor retracts the scapula and braces the shoulder. AND the rhomboid major is the same as the rhomboid minor.
• Nine muscles cross the shoulder joint and attach to the humerus. Two are axial muscles attaching to the axial skeleton (Pectoralis major & Latissimus dorsi) while the others are seven muscles with scapular attachments (Deltoid, Teres major, Coracobrachialis, Supraspinatus, Infraspinatus, Teresminor, and Subscapularis).
• The Pectoralis major flexes, adducts, and medially rotates the humerus. The Latissimus dorsi adducts and medially rotates the humerus. The Deltoid rotates and abducts the arm and is an intramuscular injection site. The Teres major is an extension and medial rotation of the humerus. The Coracobrachialis flexes and medially rotates the arm. The remaining four form the rotator cuff that reinforces the shoulder joint.
• Rotator cuff muscles are tendons of four scapular muscles that form the rotator cuff. Its acronym is “SITS muscles”(Supraspinatus, Infraspinatus, Teres minor, & Subscapularis). The tendons of these muscles merge with the joint capsule of the shoulder as they cross it en route to the humerus. They hold the head of the humerus into the glenoid cavity. The supraspinatus tendon is easily damaged.
• Muscles that act on the elbow and forearm are located in both the brachium (arm) and the antebrachium (forearm). They have four motions; Flexion, Extension, Pronation, & Supination (FEPS).
• Muscles with bellies in the arm are (brachium). Elbow flexors are the anterior compartment. The principal flexor for Elbow flexors is the Brachialis as the Brachialis is the prime mover of elbow flexion. The Synergistic flexors of Elbow flexors are the Biceps brachii and the biceps brachii produces 50% less power than the Brachialis. The Elbow extensor is the posterior compartment. The principal extensor for the Elbow extensor is the Triceps brachii as the triceps brachii is the prime mover of elbow extension.
• Muscles with bellies in the forearm are the antebrachium. Brachioradialis is the synergistic elbow flexor, the pronator quadratus is the prime mover in forearm pronation, the pronator teres assists the pronator quadratus in pronation, & supinator supinates the forearm.
• The anterior group of the muscles acting on the wrist and hand are the intrinsic muscles in the hand itself and the extrinsic muscles in the forearm. Extrinsic muscle actions include the flexion and extension of the wrist and digits, radial and ulnar flexion, finger abduction and adduction, & thumb opposition.
• The anterior (flexor) compartment of the muscles acting on the wrist and the hand (the superficial layer) includes; The flexor carpi radialis, the flexor carpi ulnaris, and the flexor digitorum superficialis.
• The Posterior (extensor) compartment (superficial layer) of the muscles acting on the wrist and hand includes the extensor carpi radialis longus, the extensor carpi radialis brevis, and the extensor digitorum.
• The Flexor retinaculum is a bracelet-like fibrous sheet, that is passed under by flexor tendons crossing the wrist.
• Carpal tunnel syndrome


  Occurs when there is a tight space between the flexor retinaculum and the carpal bones in the wrist
• Carpal tunnel syndrome


  • Repetitive motions of the wrist and fingers over a prolonged period of time
  • Inflammation, swelling, or fibrosis of tissues in the carpal tunnel
  • Pressure on the median nerve in the wrist, as well as the flexor tendons
• Treatment options for carpal tunnel syndrome

  1. Anti-inflammatory drugs

  2. Immobilization of the wrist

  3. Surgery to remove part or all of the flexor retinaculum
• The body’s largest muscles are found in the lower limb. The are less for precision, and more for the strength needed to stand, maintain balance, walk, and run. Several of these muscles cross and act on two or more joints. The Leg is the part of the limb between the knee and ankle and, the Foot includes the tarsal region (ankle), metatarsal region, and the toes.