upper extremities 2

• ANTERIOR COMPARTMENT OF THE FOREARM


  Mostly innervated by median nerve, but some will be ulnar nerve

  ULNAR NERVE: flexor carpi ulnaris and medial half of flexor digitorum profundus

  Common action is to flex the wrist joint

  Common origin of most is from the medial epicondyle
• Superficial Muscles of the Anterior Compartment


  Pronator teres

  Flexor carpi radialis

  Palmaris longus

  Flexor carpi ulnaris
• DESC: Pronator teres


  Short muscle

  Two headed muscle
• ORIGIN: Pronator teres


  One head originates from medial epicondyle of the humerus

  The other head originates from the coronoid process of the ulna
• ACTION: Pronator teres


  pronates the forearm
• INNERVATION: Pronator teres


  Innervated by the median nerve
• INSERTION: Pronator teres


  lateral surface of radius
• ORIGIN: Flexor carpi radialis


  Originates from the medial epicondyle
• INSERTION: Flexor carpi radialis


  Inserts into the bases of the second and third metacarpals
• ACTION: Flexor carpi radialis


  Very powerful flexor of the wrist joint

  Can also abduct the wrist (radial deviation)
• INNERVATION: Flexor carpi radialis


  Innervated by the median nerve
• DESC: Palmaris longus


  Thin muscle

  Common muscle that is not present in 10% of people

  Small muscle with a long insertional tendon
• Commonly used for tendon grafts

  Palmaris longus
• ORIGIN: Palmaris longus


  Originates from the medial epicondyle
• ACTION: Palmaris longus


  Functions to tense the skin of the palm

  Improves grip slightly

  No actual motion for a joint

  Synergist for some flexion of the wrist or the elbow
• INSERTION: Palmaris longus


  Inserts into the palmar aponeurosis
• DESC: Flexor carpi ulnaris


  Most medial muscle in the superficial group
• ORIGIN: Flexor carpi ulnaris


  Originates from the medial epicondyle
• INSERTION: Flexor carpi ulnaris


  Inserts into the pisiform and hamate as well as the base of the 5th metacarpal
• INNERVATION: Flexor carpi ulnaris


  Innervated by the ulnar nerve
• ACTION: Flexor carpi ulnaris


  Flexes the wrist joint

  Because of its ulnar location it can also adduct the wrist joint (ulnar deviation)
• Intermediate Muscles of the Anterior Compartment


  Flexor digitorum superficialis
• ORIGIN: Flexor digitorum superficialis


  Originates from the medial epicondyle
• INSERTION: Flexor digitorum superficialis


  Once it becomes a tendon it will individually insert into the fingers (specifically at the bases of the middle phalanges)
• ACTION: Flexor digitorum superficialis


  Main action is to flex the finger

  Specifically the proximal interphalangeal joint (between middle phalanx and proximal phalanx)
• INNERVATION: Flexor digitorum superficialis


  median nerve
• Deep Muscles of the Anterior Compartment


  are mostly innervated by the median nerve (anterior interosseous nerve)
• DESC: Flexor pollicis longus


  Partly covered by the flexor digitorum superficialis

  Lateral and just parallel to the flexor digitorum profundus
• ORIGIN: Flexor pollicis longus


  Originates from the anterior surface of the radius
• INSERTION: Flexor pollicis longus


  Inserts into the thumb (distal phalanx)
• ACTION: Flexor pollicis longus


  flexion of the interphalangeal joint of the thumb
• INNERVATION: Flexor pollicis longus


  Innervated by the anterior interosseous branch of the median nerve
• Deep muscles of the anterior compartment


  Flexor pollicis longus

  Flexor digitorum profundus

  Pronator quadratus
• ORIGIN: Flexor digitorum profundus


  Originate from the anteromedial surface of the ulna and the interosseous membrane
• INSERTION: Flexor digitorum profundus


  Inserts far more distal than the flexor digitorum superficialis, inserts into the base of the distal phalanges
• ACTION: Flexor digitorum profundus


  Action: flexion of the distal interphalangeal joint

  Joint between the distal phalanx and the middle phalanx

  Because of the course through the entire finger, it also crosses over the proximal interphalangeal joint

  It can also aid in the flexion of the proximal interphalangeal joint
• INNERVATION: Radial/lateral half of flexor digitorum profundus


  index and middle fingers

  Innervated by the median nerve (anterior interosseous branch)
• INNERVATION: Ulnar/medial half of flexor digitorum profundus


  ring and little finger

  Innervated by ulnar nerve
• Only muscle capable of flexing the distal interphalangeal joint


  Flexor digitorum profundus
• DESC: Pronator quadratus


  Deepest muscle in the distal forearm

  A little oblique in orientation