BMS Anatomy Asynchronous Lecture 10 PDF

BMS Anatomy Asynchronous Lecture 10 Elbow, Radioulnar and Hand Joints Presented By: Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Author), 9th ed. Upper Limb Chapter; Pages:...

BMS Anatomy Asynchronous Lecture 10 Elbow, Radioulnar and Hand Joints Presented By: Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 277 - 288 Link to this module recording Boucher Campus: https://ccnm.ca.panopto.com/Panopto/Pages/Viewer.aspx?id =8a4c261f-8a69-472f-ac21-af4f005a28b8&instance=Moodle Toronto Campus: https://ccnm.ca.panopto.com/Panopto/Pages/Viewer.aspx?id =0e1e1eed-122d-493f-aba7-af4f005a37a0&instance=Moodle Elbow Complex Contains three bony articulations all within a single joint capsule. o Humero-ulnar (Trochlea of humerus articulates with the trochlear notch of the ulna) o Humero-radial (Capitulum of humerus articulates with the head of the radius o Proximal Radio-ulnar The first two joints (humero-ulnar and humero-radial) are what we typically think of as “elbow” joint. This is a synovial hinge joint (one degree of freedom). The elbow joint permits flexion and extension movements. It is a very strong joint structurally due to the bony configuration (primarily between the humerus and ulna) and the collateral ligaments (radial collateral and ulnar collateral ligaments). Elbow Joint Articular Surfaces & Capsule The distal end of the humerus has two articular surfaces (A): the trochlea (2) and the Capitulum (3). The proximal ends of the two bones of the forearm have two surfaces corresponding to those of the humerus: the trochlear notch of the ulna, which articulates with the trochlea and has corresponding shape. Figure (C) , shows the coronoid fossa (5) above the trochlea and the radial fossa (6), the medial epicondyle (7), and the lateral epicondyle (8). Figure (F), shows also the olecranon fossa (17) which receives the olecranon process (20). A coronal section taken through the joint (D), shows the capsule (17) invests a single anatomical joint cavity with two functional joints: the true elbow joint (vertical strips in fig. E) and the superior radioulnar joint (horizontal strips). The olecranon process is also seen (11) lying inside the olecranon fossa during extension. Axis of Motion Can be approximately located on humans slightly distal to the epicondyles of the humerus. Carrying Angle The trochlea extends more distally than the capitulum; hence the axis for flexion and extension is not fully perpendicular to the humeral shaft. With the elbow at full extension and the forearm supinated (i.e. anatomical position), the forearm deviates laterally in relation to the humerus; this is the Carrying Angle Ranges from 5 - 19 Typically women have a more pronounce carrying angle by 0 - 6,due to the wider pelvic girdle exhibited in women. The carrying angle permits the arm to be swung without contacting the hips. Cubitus Varus & Cubitus Valgus Cubitus varus (varus means a deformity of a limb in which part of it is deviated towards the midline of the body) is a common deformity in which the extended forearm is deviated towards midline of the body Cubitus valgus is a medical deformity in which the elbow is turned in. Elbow Joint Ligaments ❖ The main function of these ligaments is to keep the articular surfaces in apposition. They are located on either side of the joint; the medial (ulnar) collateral ligament (1,2,3 in A) and the lateral (radial) collateral ligament (10,11,12 in B). ❖ These ligaments will also keep the half-ring (C) fitted to the pulley and prevent all sideways movements (E). ❖ The capsule is strengthened anteriorly by the anterior ligament (14) and oblique anterior ligament (15). Elbow Joint Ligaments Flexor & Extensor Muscles of the Elbow ❖Extension of the elbow depends on one muscle, i.e. the triceps brachii (A), as the anconeus exerts minor action. The lateral head of the triceps (2) is the strongest of the three heads. ❖There are three major flexor muscles: 1. 2. Brachialis (B,1), and brachioradialis (B,2) act exclusively as a flexor of the elbow. Biceps brachii (C), by virtue of its origin from the scapula, keeps the articular surfaces of the shoulder in opposition, but its main action is to flex the elbow. It is also the main supinator of the forearm. Elbow Joint AROM & PROM The position of reference (C) is defined as the position achieved when the axes of the arm and forearm are in a straight line. The range of extension, starting from the position of reference, is 0° except in subjects (e.g. women and children) in whom great laxity of the ligaments allow hyperextension of 5° to 10°. By contrast, relative extension is always possible from any position of flexion. Active flexion (A) has a range of 145°, and the range of passive flexion is 160° (with the fist width separating the wrist from the shoulder. 1 1 2 Movement Elbow Flexion (active) Elbow Flexion (passive) Elbow Extension Degrees 145 160 0 Proximal (Superior) Radio-Ulnar Joint This joint is a synovial pivot joint with cylindrical surfaces and one type of movement: i.e. rotation about the axis of the two cylinders in contact. It consists of the following two cylindrical surfaces: The head of the radius (C), with its cylindrical rim (1) covered by articular cartilage. The cupped surface of the head (fovea) also articulates with the capitulum of the humerus. A fibro-osseous ring (A): consists of the following: 1. The radial notch of the ulna (6) is covered by the articular cartilage, concave anteroposteriorly. 2. The annular ligament (5) consists of a strong fibrous band attached by its ends to the anterior and posterior margins of the radial notch of the ulna and lined internally by cartilage continuous with that lining the radial notch. Inferior (Distal) Radio-Ulnar Joint This joint, like the superior radio-ulnar joint, has cylindrical surfaces, i.e. head of the ulna and the ulnar notch of the radius. It has only one degree of freedom (rotation) thus, it is a synovial pivot joint. At the distal edge of the ulnar notch is inserted the articular disc (5), which is attached above to the base (9) of the styloid process of the ulna (B). The purpose of the disk is to bind the radius and ulna together and separate the distal radioulnar joint and ulna from the radiocarpal joint. The proximal & distal surfaces of the disc are covered by articular cartilage The thickening of the capsule as the palmar (anterior) and posterior or dorsal radioulnar ligaments support the joint anteriorly and posteriorly (Refer to the image on the next page). Middle Radioulnar joint A ligamentous connection, the interosseous membrane, lies between the bodies of the radius and ulna. Defined as an amphiarthrosis, Syndesmosis joint. Supinator & Pronator Muscles Movement Degrees 1 Supination 90 2 Pronation 80 17 Motions and Activity of Elbow Joint Complex in Function ❑Can you squeeze your fist maximally without contracting your triceps brachii? Contraction in both the elbow flexors and the triceps brachii with a tension roughly proportionate to the amount of force produced at the fist ❖To stabilize the elbow (not waste energy in elbow movement) ❖ To stabilize the proximal attachments of the dynamometer finger and wrist muscles Articular Complex of the Wrist ❖ This complex (A) from structural point of view is comprised of three components: 1. The radio-carpal joint between the distal end of radius, disc of the distal radiocapal joint (proximally), and the proximal row of carpal bones (except pisiform) distally. This is an condyloid (ellipsoid) joint (B) with an anterior-posterior axis (BB’) which is related to movements of adduction and abduction and a transverse axis (AA”) which is related to flexion and extension. 2. The mid-carpal joint, a synovial planar (plane) joint between the proximal and distal rows of carpal bones (except pisiform). 3. Intercarpal joints; a group of small synovial planar joints between the proximal or distal carpal bones. ❖ The ligaments of the radio-carpal joint are arranged in two groups: i. The collateral ligaments (C): the lateral (1) is attached to the styloid process of the radius and the scaphoid bone. The medial (2) is attached to the styloid process of ulna and the pisiform and triquetrum bones. ii. The anterior and posterior ligaments (C): the radiocarpal (3) with its expansion to the pisiform bone; the ulno-carpal (4) ligament. 19 21 Radiocarpal Joint ❖ The action of the ligaments varies with the type of movement performed. ❖ In adduction and abduction (C,D,E), the collateral ligaments are active so that, starting from the resting position, the lateral (radial) collateral ligament becomes taut and the medial (ulnar) collateral ligament relaxes during adduction and vice versa in abduction. ❖ In flexion and extension (F,G,H), the anterior and posterior ligaments are involved so that, from the position of rest, the posterior ligament becomes taut in flexion and the anterior ligament in extension. 22 Radiocarpal Joint AROM In general the range of abduction and adduction is minimal when the wrist is fully flexed or extended, because of the tension developed in carpal ligaments. It is maximal when the hand is in the plane of reference or slightly flexed, because the ligaments are relaxed. The axis of these motions is through the head of the capitate, located proximally to the base of MC III. 1 2 Movement Degrees Radial Deviation 15 Ulnar Deviation 30 23 Radiocarpal Joint AROM 1 2 Movement Wrist Flexion Wrist Extension Degrees 85 85 24 Synergists and Antagonists of Wrist Joint ❖ Wrist Flexion & Extension – which muscles are involved? Wrist Flexion: a combined effort by 1.Flexor Carpi Radialis 2.Flexor Carpi Ulnaris 3.Palmaris Longus 4.Flexor Digitorum Superficialis 5.Flexor Digitorum Profundus 6.Flexor Pollicis Longus Wrist Extension: a combined effort by 1.Extensor Carpi Radialis Longus 2.Extensor Carpi Radialis Brevis 3.Extensor Carpi Ulnaris 4.Extensor Digitorum 5.Extensor Digiti Minimi 6.Extensor Pollicis Longus 7.Extensor Pollicis Brevis 8.Extensor Indicis 25 Synergists and Antagonists of Wrist Joint ❑ Wrist Adduction & Abduction A synergistic combination of the wrist flexors and extensors results in adduction and abduction: Wrist Adduction: a combined effort by 1.Flexor Carpi Ulnaris 2.Extensor Carpi Ulnaris Wrist Abduction: a combined effort by 1.Flexor Carpi Radialis 2.Extensor Carpi Radialis Longus 3.Extensor Carpi Radialis Brevis 4.Abductor Pollicis Longus 26 Carpometacarpal (CMC) Joint  The CMC joint of the thumb is a synovial saddle joint (with 3 DOF), with the surfaces of the 1st metacarpal and the 1st CMC trapezium both having convex and concave characteristics. st 1 CMC The joint capsule is thick, but loose. st Motions include abduction/adduction (in a right angle to 1 CMC the palm), and flexion/extension (parallel to the palm), and opposition (a rotation of the 1st metacarpal on the trapezium). Due to the laxity of the joint, 15 to 20 of rotation is possible. flexion 15 extension 20 abduction 70 2nd to 5th Carpometacarpal (CM) Joints The distal row of carpal bones articulate with the bases of the 2 nd to 5th metacarpals in an irregular manner. A common joint cavity is found between the four distal carpals, the CMC joints, and into the intermetacarpal joints. The 2nd and 3rd CMC joints have a motion of 2 or less. The 4th CMC joint has 10 to 15 of dorso-volar movement. The 5th CMC joint is the most flexible, with 25 to 30 of motion. These movements are important to hand function with relation to the transverse arch of the hand from the closed fist to the open hand. Metacarpophalangeal (MCP) Joints Synovial condyloid joints between the heads of the metacarpal bones and the base of the proximal phalanges of the digits with 2 DOF. Medial and lateral collateral ligaments attach the heads of the metacarpals to the bases of the phalanges. They are also supported by the palmar plates (ligaments) ventrally. ❑ Movements and ROM – MCP joints, digits II – V When the MCP joint is in 90 of flexion, the collateral ligaments are taut 1 2 3 4 5 6 Movement MCP Flexion MCP Hyperextension MCP Abduction MCP Adduction MCP Abd. (w fingers flexed) MCP Add. (w fingers flexed) Degrees 90 0 - 45 20 20 0 0 Interphalangeal (IP) Joints Digits II to V have two interphalangeal joints; the Proximal Interphalangeal (PIP) joint and the Distal Interphalangeal (DIP) joint. Thumb only has one IP joint. Classified as hinge joints with 1 DOF 1 2 3 4 Movement Degrees PIP Flexion 120 DIP Flexion 90 PIP and DIP Extension 0 Thumb IP Hyperextension 5 - 10 Movements and ROM of the Thumb MCP Joint In full flexion and extension, the MCP joint of the thumb cannot perform any significant abduction or adduction due to the tightening of surrounding joint ligaments. In semiflexion, approximately 5 - 10 of abd/add can occur 1 2 3 Movement Degrees MCP Thumb Flexion 45 - 60 MCP Hyperextension 0 - 20 IP flexion 90 Muscles acting on Digits A.Extrinsic Muscles 1. Extensor Digitorum 2. Extensor Indicis 3. Extensor Digiti Minimi 4. Extensor Pollicis Longus 5. Extensor Pollicis Brevis 6. Abductor Pollicis Longus 7. Flexor Digitorum Superficialis 8. Flexor Digitorum Profundus 9. Flexor Pollicis Longus B.Intrinsic Muscles 10.Central muscles a)Four Lumbricals b)Three Palmar Interossei c)Four Dorsal Interossei d)Adductor Pollicis B.Intrinsic Muscles 10.Thenar Muscles: a)Opponens Pollicis b)Abductor Pollicis Brevis c)Flexor Pollicis Brevis 11.Hypothenar Muscles: a)Opponens Digiti Minimi b)Abductor Digiti Minimi c)Flexor Digiti Minimi Brevis d)Palmaris brevis Muscle Actions for Specific Movements Flexion of Digits 2 to 5 1. FDS 2. FDP 3. Lumbricals 4. Dorsal interossei 5. Palmar interossei 6. Flexor digiti minimi Extension of Digits 2 to 5 1. 2. 3. 4. 5. 6. Ext. digitorum Ext. digiti minimi Ext. indicis Lumbricals Dorsal interossei Palmar interossei Abduction of Digits 2 to 5 1.Dorsal interossei 2.Abductor digiti minimi (digit V) Adduction of Digits 2 to 5 1.Palmar interossei Opposition of Digits V 1. Opponens digiti minimi Muscle Actions for Specific Movements Flexion of Thumb 1. FPL 2. FPB Extension of Thumb 1. EPL 2. EPB Adduction of Thumb 1. Adductor pollicis Abduction of Thumb 1. Abductor pollicis longus 2. Abductor pollicis brevis Abduction of Thumb 1. Abductor pollicis longus 2. Abductor pollicis brevis Opposition of Thumb 1. Opponens pollicis