1. Topic
2. The ulnar claw hand in ulnar nerve lesions compared with the claw in brachial plexus (or combined ulnar and median nerve) injuries. - There is pronounced loss of fingers aDDuction; the patient can NOT grasp tightly a piece of paper between the fingers, because all the interosseus muscles are paralyzed. - The ulnar nerve also supplies sensory fibers to 1 1/2 fingers as well as motor fibers to 1 1/2 muscles in the forearm.
3. -RAt Trys to D/C from Behind=Roots. rAmi,Trunk, Division, Cord, Branches. - the pupils of the eyes are posterior (dorsal) root ganglia. - The brachial plexus originates from anterior rami. - rAmi,Trunk, Division, Cord, Branches are outside the intervertebral foramina, there are also - The lnower "trunk" of the brachial plexus overlies the first
   1. ***Brachial plexus ROOTS: - sensory and motor Root within the spinal canal. roots fuse at about the level of the intervertebral foramina, forming the spinal nerve which divides into anterior and posterior rami. -the roots fuse at about the level of the intervertebral foramina, forming the spinal nerve which divides into anterior and posterior rami. The brachial plexus originates from anterior rami. -The spinal nerve roots. Each pair of sensory and motor nerve roots (cervical, thoracic and lumbar) joins in the intervertebral foramen to form a spinal nerve. Once outside the vertebral canal the spinal nerve divides into a posterior (dorsal) and an anterior (ventral) ramus, -EACH of which contains a mixture of motor and sensory fibers. -The sacral nerve roots, however, are so long, be- ing part of the cauda equina. that they can't wait to get to the sacral foramina; -the roots fuse and form spinal nerves while in the vertebral canal and also divide into posterior and anterior rami within the canal. -Thus each sacral nerve has two exit points (not just one intervertebral foramen) - a posterior and an anterior foramen on either side of the sacrum, for the posterior and anterior rami. -Posterior rami supply skin near the middle of the back, as well as midline skeletal muscles of the spine (fig. 12-7). ***Anterior rami supply the rest of the neck, trunk, and extremities. The cervical, brachial and lumbosacral plexuses consist of extensions of anterior rami.
   2. Rami : posterior and anterior rami together combine to form the dermatome map of the body: Ct - no sensory dermatome C2 - a skull cap C3 • a high collar. as found on a turtleneck sweater C4 - a cape around the shoulder C5-Tl - upper extremities t.humb-suckers suck C6 T5 - nipple T10 - belly button L 1 - Inguinal Ligament(i.e. L1 = IL) * L4 knee (also the nerve mediating the knee jerk reflex~ L4 also provid~ sensation to the big toe, which kicks the examiner testing the knee jerk reflex. L5 - three middle toes (between U and 81) *s1 - ankle jerk reflex (poor L5 has no reflex) s1-s2 - predominantly on the rear of the lower extremi- ties. s2-s5 - genital and anal zones
   3. TRUNK : Relations of the brachial plexus and first rib: 1. The brachial plexus passes between the first rib and clavicle. 2. The 3 trunks of the plexus lie at about the level of the first rib. 3. The plexus rami lie in the neck, whereas the divisions and cords lie in the axilla The lower brachial plexus trunk and the subclavian artery circulation may be compromised if there is exces- sive hypertrophy of the anterior scalene muscle (scalenus anticus syndrome or an extra cervical rib.
   4. Topic
      1. #1 Waiter's tip injury= shoulder inturning + pronation = waiter's tip posture= denervated suprascapular nerve to the infraspinatus muscle---> The shoulder becomes inturned AND denervated musculocutaneous n.--> biceps loss leads to pronation AND There will also be loss of skin sensation in a C5C6 distribution. +/- weakness near the middle of the back present IF the roots of C5 and/or C6 have been pulled out and the posterior rami
      2. #2 Clawhand. nerve trunk injury=weak ulnar and median n.= loss of lumbricales--> loss of the "L"-shape & weak wrist flexion & Sensory defects will occur in a C8TI distribution -pathology: extra cervical (C7) rib or by sudden pulling of the arm as intrying to break one's fall; .
      3. #3 Ms. C7's wrist will DROP to brush off Mr.C8T1's hand away from her CRUCH.=Radial n. injury=difficulty in extending the wrist or fingers. or the elbow. Pathology: crutch pressure, saturday night's palsy
      4. #4Mr.C5C6 & Ms. C7. LOATH (LOng THoracic nerve) Mr.C8T1 and are looking daggers at him = long thoracic n. injury--->loss of serratus anterior muscle= Winging scapula when the patient pushes against a wall -pathology: post-mastectomy, any inury near the vertibral column
4. axillary
   1. sensory
      1. Skin overlying deltoid muscle Suprascapular nerve
   2. motor
      1. Topic
      2. Axillary nerve ● Deltoid
   3. regional anatomy
      1. -3 spaces produced by the 3 "T"s: Triceps, Teres major, and Teres minor. -axillary nerve passes through the quadrangular space to wrap around the surgical neck of the humerus. Fractures of the surgical neck may thus injure the axillary nerve.
      2. axilla: The walls olthe axilla are paneled: 1. anteriorly : the pectoralis major (felt in the anterior skin fold). 2. posteriorly : the latissimus dorsi and the teres major muscles (felt in the posterior skin fold), and the scapula. 3. medially : the serratus anterior muscle, which lies against the rib cage.
5. musculocutaneous
   1. sensory
      1. ● Musculocutaneous nerve Radial volar forearm (lateral antebrachial cutaneous nerve)
   2. motor
      1. Musculocutaneous nerve ● Biceps
6. radial
   1. pathology: fractures of the humerus may injure the radial nerve since this nerve lies in the radial sulcus, which indents the humerus. Fracture below the midshaft of the humerus spares the ability to extend the elbow, as
   2. sensory
      1. Radial sensory nerve in forearm ● Dorsal radial aspect of hand Radial nerve proximal to elbow ● No unique sensory site
   3. regional anatomy
      1. -The median nerve accompanies the brachial artery; -The radial nerve accompanies the profunda brachii artery in a spiral groove in the humerus; -The ulnar nerve accompanies the superior ulnar collateral artery.
   4. motor
      1. test
         1. Radial nerve at elbow ● Extensors of wrist, thumb, and all fingers Radial nerve proximal to elbow ● Brachioradialis, triceps
7. median n.
   1. sensation
      1. Median nerve at wrist ● Index finger pulp (radial sensory can innervate thumb pulp) Median nerve in forearm ● Thenar eminence (palmar cutaneous branch of median nerve arises proximal to carpal tunnel)
   2. regional anatomy
      1. The median nerve accompanies the brachial artery; The radial nerve accompanies the profunda brachii artery in a spiral groove in the humerus; the ulnar nerve accompanies the superior ulnar collateral artery.
         1. - The cubital fossa, anterior view. is a roughly triangular area, bound by the brachioradialis laterally, the pronator teres medially and by an imaginary line between the humeral epicondyles. - median & radial nerves also lie deeply & centrally. The radiaL nerve lies LateraL to the biceps muscle, and the Median nerve lies Medial. -The pulse may be palpated just medial to the biceps muscle and tendon. The bicipital aponeurosis separates the brachial artery from the more superficial veins, a useful point to remember in performing a venous cutdown procedure.
         2. The cross section is at the level of the distal radius. in a suicide attempt, by wrist slashing, -Arterial hemorrhage implies deeper damage - Cut #1, on the radial side, would damage four main structures: 1. the radial artery (prior to its dive into the anatomical snuff box), or its superficial palmar branch, which joins the superficial palmar arch 2. the flexor carpi radialis (wrist will then deviate to the ulnar side on attempted flexion) 3. the median nerve (causing difficulty with thumb opposition) 4. palmaris longus (causing weakness in wrist flexion) -Cut #2. on the ulnar side, would sever three main structures: 1. the ulnar artery. 2. flexor carpi ulnaris (causing deviation of the wrist radially on attempted flexion) 3. the ulnar nerve (causing paralysis of most of the small hand muscles - claw hand). With deeper midline incisions, the tendons of flexor digitorum superficialis Note that the flexor retinaculum attaches to the 4 corners of the two rows of carpal bones. the trapezIUM is under the ThUM, and the Pisiform is Proximal to the hook of hamate
   3. motor
      1. forearm:The finger flexion muscles
      2. hand: innervating 2 lumbrical muscles; & thenar muscles of the thumb
      3. tests Median nerve at wrist ● Abductor pollicis brevis, opponens pollicis brevis (with other median-innervated muscles being normal) Median nerve in forearm ● Flexor pollicis longus, flexor profundus to index finger, pronator teres, flexor superficialis
8. ulna
   1. sensory
      1. Ulnar nerve at wrist ● Little finger pulp Ulnar nerve at elbow ● Dorsal ulnar aspect of hand
   2. motor
      1. Ulnar nerve at wrist ● Abductor digiti minimi, first dorsal interosseous (with flexor profundus to little finger being normal) Ulnar nerve at elbow ● Flexor profundus to little finger, flexor carpi ulnaris (with weakness in ulnar innervated intrinsics)
9. Suprascapular nerve ● Supraspinatus, infraspinatus Spinal accessory nerve ● Trapezius Long thoracic nerve ● Serratus anterior (scapular winging