BMS Anatomy Lecture 5: Bones of the Upper Extremity PDF

BMS Anatomy Asynchronous Lecture 5 Bones of the Upper Extremity Presented By: Moore's Clinically Oriented Anatomy, by Arthur F. Dr. K. Lumsden; [email protected] Dalley II PhD FAAA (Author), Anne M....

BMS Anatomy Asynchronous Lecture 5 Bones of the Upper Extremity Presented By: Moore's Clinically Oriented Anatomy, by Arthur F. Dr. K. Lumsden; [email protected] Dalley II PhD FAAA (Author), Anne M. R. Agur BSc (Toronto Campus) (OT) MSc PhD FAAA (Author), 9th ed. Dr. M. Doroudi; [email protected] Chapter 4 (Thorax): Pages 296 – 324 Boucher Campus) Chapter 5 (Abdomen): Pages 421 – 425  Axial & Appendicular Skeleton (Review) - The Skeletal System Axial Skeleton – 80 bones – lies along the longitudinal axis – skull, hyoid, vertebrae, ribs, sternum, ear ossicles Appendicular Skeleton – 126 bones – upper & lower limbs and pelvic & pectoral girdles Upper Limb: humerus, radius, ulna, carpal bones, metacarpal bone, phalanges Lower Limb: femur, tibia, fibula, patella, tarsal, metatarsal, phalanges Pelvic Girdle: is made by which bone? Shoulder girdle: is made by which bones? Introduction to Upper Limb  Now, before we go with the bones, I would like to actually walk you through that introduction to that to the upper limb. This this chart in the previous slide, summarizes the concept of the upper limb, the fact that upper limb is one of the main top of the body regions. (We have the head and neck, the upper limb and trunk) So then Upper Limb is one of the main regions of the human body, which includes 4 parts: - Shoulder Region - Upper Arm - Forearm - Hand We have subdivisions for the shoulder region: Deltoid Pectoral Clavicle Scapula And then when it comes to the head, it is divided into three parts: Wrist, Proper Hand Digits for fingers. Usually when I asked this during the in the in-person classes, What are these (the digits) referred to, the answer is usually the phalanges, whereas the phalanges are the bones but the “region” that are located in is referred to as digits.  We count digits from lateral or to medial plane, and are named as the index, the middle, the ring finger and the little finger or pinky finger. THUMB: The thumb is referred to as the Pollex. The term “Pollicis” is the adjective for the Thumb – means npertaining to the thumb. For example, flexor pollicis longus means muscle of the thumb. Adjective for index finger is indicis, means pertaining to index finger. For example, we have a muscle named, Extensor Indicis. MIDDLE FINGER: The middle finger doesn't have alternative name. The ring finger or the fourth finger – Why do you think the wedding ring is put on this finger? Pinky finger is called Digitus Minimus. The adjective for Digitus Minimus is Digiti Minimi. For example, Flexor Digiti Minimi. means related to that pinky finger. NOTE: Anatomically, we have five fingers. We include thumb in the fingers. The upper body regions are: - The shoulder region includes the pectoral girdle - so the clavicle and the scapula. - The arm region has the humerus - The forearm region has radius and the ulna. The hand has three regions. And each regions has bones associated to it. - Carpus has Carpal bones. - Metacarpus has Metacarpal bones - Digits has the phalanges Associated joints will be mentioned soon (THEY ARE MENTIONED IN THE CHART) So let's begin with that with the bones.  Clavicle This bone forms part of the shoulder girdle and is the only long bone that lies horizontally. The collar bone or clavicle is an “S” shaped bone, anteriorly convex in the medial 2/3 of its length, while the lateral 1/3 is concave anteriorly. Toward the sternum is the sternal end and toward the scapula the flat acromial end and between the two lies the body of the clavicle. At the sternal and acromial ends, we can find articular facets. Near the sternal end, on the lower surface of the clavicle, is the impression for the costoclavicular ligament. The subclavian groove for subclavian muscle attachment muscle lies on the inferior surface of the clavicular body. The prominent conoid tubercle lies near the acromial end close to the trapezoid line.  Scapula The scapula (shoulder blade) is a triangular flat bone that lies on the posterolateral aspect of the thorax, overlying the 2nd–7th ribs. It has a medial (vertebral) border, a lateral border, and a superior border, which are separated from each other by the superior and inferior angles and the truncated lateral angle. The anterior or costal surface is flat and slightly concave (subscapular fossa). The dorsal surface is divided by the spine of the scapula into a smaller supraspinous fossa and a larger infraspinous fossa. The spine of the scapula has a triangular base medially, which rises laterally to terminate in a flattened process, the acromion. Near the lateral end lies an oval articular facet for articulation with the clavicle, the acromial articular facet. The acromial angle is a readily palpable bony point. The lateral angle bears the glenoid cavity. At its upper border is a small projection, the supraglenoid tubercle. Below the glenoid cavity lies the infraglenoid tubercle. The neck of the scapula is adjacent to the glenoid cavity. The coracoid process lies above the glenoid cavity. It is bent at a right angle ventro-laterally. Medial to the base of the coracoid process, on the upper border of the scapula, lies the suprascapular notch.  Humerus (Proximal End and Body) The humerus consists of the body and upper (proximal) and lower (distal) ends. The proximal end is formed by the head of the humerus, adjoining anatomical neck, the greater tubercle, and the lesser tubercle. Between these tubercles, the intertubercular (bicipital) groove or sulcus is located. There is a lateral lip and a medial lip associated with the intertubercular sulcus. The surgical neck lies proximally on the body of the humerus. In the middle of the body lies laterally the deltoid tuberosity. Behind the deltoid tuberosity, there is very shallow sulcus known as radial groove (for the radial nerve). The body may be divided into an antero-medial surface with a medial border, and an antero-lateral surface with a lateral border, which become sharpened distally and is called the lateral and medial supracondylar ridges. The groove for the radial nerve lies on the posterior surface of the body.  Humerus (Distal End) The distal end of the humerus bears on its medial side the large medial epicondyle and on the lateral side the smaller lateral epicondyle. The distal end of the humerus—including the trochlea and capitulum, as well as the olecranon, coronoid, and radial fossae—makes up the condyle of the humerus. The condyle has two articular surfaces: a lateral capitulum (L., little head) for articulation with the head of the radius and a medial, spool-shaped or pulley- like trochlea (L., pulley) for articulation with the proximal end (trochlear notch) of the ulna. The radial fossa lies proximal to the capitulum, and proximal to the trochlea is the somewhat larger coronoid fossa (Both fossae are on the anterior surface of the distal end) Medial to the trochlea, there is a shallow groove, the sulcus for the ulnar nerve. On the posterior surface above the trochlea is a deep pit, the olecranon fossa.  Radius The radius is the shorter bone on the lateral side of the forearm and consists of a shaft and proximal and distal ends. At the proximal end is the head of the radius bearing the fovea articularis, which is continuous with the articular circumference. On the transition between the neck of the radius and the shaft lies the radial tuberosity. In transverse section the shaft is almost triangular with a medially facing interosseous border. At the lower end of the radius lies the styloid process and medial to it, is the ulnar notch. The carpal articular surface faces distally. Dorsally we find a number of grooves of variable depth in which run the tendons of the long extensor muscles. The bony elevation, which lies on the dorsal surface of distal end is called the dorsal tubercle or Lister’s tubercle. Ulna The ulna is the medial and longer of the two forearm bones. For articulation with the humerus, the ulna has two prominent projections: (1) the olecranon, which projects proximally from its posterior aspect, and (2) the coronoid process, which projects anteriorly. The olecranon and coronoid processes form the walls of the trochlear notch. Inferior to the coronoid process is the tuberosity of the ulna. On the lateral side of the coronoid process is a rounded concavity, the radial notch, which receives the broad periphery of the head of the radius. Inferior to the radial notch on the lateral surface of the ulnar shaft is a prominent ridge, the supinator crest. Between it and the distal part of the coronoid process is a concavity, the supinator fossa. The shaft of the ulna has a medial (interosseous) border that gives attachment to the interosseous membrane. At the distal end of the ulna is the head of the ulna with a small, conical ulnar styloid process.  Carpal Bones These bones, 8 in number, are arranged in two rows of four. In the proximal row from lateral to medial are the scaphoid, lunate, triquetrum, and superimposed on it the pisiform. In the distal row from lateral to the medial side are the trapezium, trapezoid, capitate and hamate. The scaphoid is the largest bone in the proximal row. On its palmar surface is a tubercle. On the palmar surface of the hamate, there is the hamulus (hook of hamate), which is curved laterally.  Carpal Arch & Tunnel The eight carpal bones form an arch, the carpal arch, which is concave anteriorly. The arch is converted into a tunnel by the thinking of the deep fascia on the anterior wrist known as flexor retinaculum to a tunnel, the carpal tunnel. Nine tendons and a nerve pass through the tunnel from the forearm to the hand. We learn about these structures later in the course.  Metacarpal bones & Phalanges The five metacarpals of the hand each has a head, a shaft and a base. On all of them, there are articular facets at one end (base) for articulation with the carpals and at the other end (head) for the proximal phalanges. Each digit consists of more than one bone, namely a proximal, a middle and a distal phalanx. The only exception is the thumb which has only two phalanges, a proximal and a distal. Each phalange has a shaft, a head, and a base.