Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Transcription

1 The Upper Limb The upper limb consists of the arm (brachium), forearm (antebrachium), and hand (manus) Thirty-seven bones form the skeletal framework of each upper limb

2 Arm Articulates with the scapula at the shoulder Articulates with the radius and ulna at the elbow Proximal end (head) fits into the glenoid cavity of the scapula Anatomical neck: constriction inferior to the head Tubercles: Greater & lesser separated by intertuberchlar sulcus (bicipital groove) Site of muscle attachment for the rotator cuff muscles The intertubercular sulcus guides a tendon of the biceps to its attachment point at the rim of the glenoid cavity

3 Arm Surgical neck: common site of fractures Deltoid tuberosity: attachment site of the deltoid muscle of the shoulder Radial groove: marks the course of the radial nerve Medial and lateral epicondyles which are points of muscle attachment Coronoid fossa (anterior) and olecranon fossa (posterior): depressions that allow the corresponding processes of the ulna to move freely Radial fossa: receives the head of the radius when the elbow is flexed

4 Bones of the Forearm (antebrachium): Radius and Ulna Figure 7.24

5 Forearm Can palpate the radius and ulna along their entire length unless you are very muscle bound The radius and ulna articulate proximally with the humerus and distally with the wrist bones radioulnar joints: joints where the radius & ulna articulate both proximally and distally Interosseous membrane: connects the radius & ulna along their entire length The radius and ulna form an X when pronated.

6 Ulna Slightly longer than the radius Forms the elbow joint w/ the humerus Proximal end bears: Olecranon process Coronoid process These processes are separated by the trochlear notch These processes grip the trochlea of the humerus (hinge joint) Thus, when fully extended, the olecranon process of the ulna locks into the olecranon fossa of the humerus and prevents hyperextension Posterior olecranon process: forms the angle of the elbow when flexed Radial notch: site where the ulna articulates w/ the head of the radius

7 Radius The major forearm bone contributing to the wrist The radius lies opposite (lateral to) the ulna and is thin at its proximal end, widened distally (the opposite of the ulna) The superior surface of the head is concave and articulates w/ the capitulum of the humerus Medially, the head articulates with the radial notch of the ulna Major markings include: the radial tuberosity: anchor site for the biceps ulnar notch: located distally and articulates w/ the ulna styloid process: anchoring site for ligaments running to the wrist

8 Radius and Ulna Figure 7.24

9 Hand Skeleton of the hand contains wrist bones (carpals), bones of the palm (metacarpals), and bones of the fingers (phalanges) Figure 7.26a

10 Comparison of Male and Female Pelves Table 7.4.1

11 Pelvic Girdle (Hip) Attaches the lower limbs to the axial skeleton Transmits the weight from the upper body to the lower body Supports the visceral organs of the pelvis Lacks mobility, but has greater stability Hip bones = os coxae (coxal bone) unite anteriorly and with the sacrum posteriorly Bony pelvis = a deep basin-like stucture formed by the coxal bones, sacrum, and coccyx Coxal bone cosists of 3 bones (at childhood) Ilium Ischium Pubis These bones are fused in adults with their names being the regions of the coxal bone Acetabulum: receives the head of the femur (otherwise known as the hip joint)

12 Ilium The ilium is a large flaring bone that forms the superior region of the coxal bone It consists of a body and a superior winglike portion called the ala (where the iliac crests are found) Sites of muscle attachment are: Anterior superior iliac spine Posterior inferior iliac spine Posterior superior iliac spine Anterior inferior iliac spine Greater Sciatic notch: passage for the sciatic nerve to the thigh Gluteal surface: consists of the posterior, anterior, and inferior gluteal lines. Serves as the attachment of the gluteal muscles

13 Ilium The auricular surface articulates with the sacrum forming the sacroiliac joint The weight of the body is transferred through the spine to the pelvis through this joint The body of the ilium joins the pubis Major markings include the iliac crests, four spines, greater sciatic notch, iliac fossa, arcuate line, and the pelvic brim

14 Ischium The ischium forms the posteroinferior part of the hip bone The thick body articulates with the ilium, and the thinner ramus articulates with the pubis anteriorly Ischial spine: projects medially into the pelvic cavity Is the point of attachment for the sacrospinous ligament running from the saccrum Lesser sciatic notch: passage for nerves and blood vessels to serve the anogenital area Ischial tuberosity: a thickened area that is the strongest part of the hip bones (You are sitting on it right now!!!) Also functions as the attachment site for the muscels of the hamstring Sacrotuberous ligament: a massive ligament running from the sacrum to each ischial tuberosity. Functions to hold the pelvis together

15 Pubis The pubic bone forms the anterior portion of the hip bone It articulates with the ischium and the ilium The urinary bladder rests upon it V shaped with superior and inferior rami issuing from a flattened medial body. Pubic crest: lateral end is the pubic tubercle and the attachment point for the inguinal ligament Obturator foramen: passage way for blood vessels and nerves, but is mostly filled with fibrous membranes Pubic symphisis joint: where the bodies of the 2 pubic bones are joined by a fibrocartilage disc Pubic arch: the acuteness of the angle of this structure defines a male vs. female hip

16 Comparison of Male and Female Pelvic Structure Male pelvis Tilted less forward Adapted for support of heavier male build and stronger muscles Cavity of true pelvis is narrow and deep Female pelvis Tilted forward, adapted for childbearing True pelvis defines birth canal Cavity of the true pelvis is broad, shallow, and has greater capacity Female Male

17 Pelvic Structure and Child Bearing The pelvic brim separates the false (greater) and true (lesser) pelvis False pelvis: True pelvis: Supports abdominal viscera Does not restrict childbirth Surrounded by bone Contains the pelvic organs

18 Pelvic inlet IS the pelvic brim During child birth, the soon-to-be-newborn s forehead faces one ilium and it s occiput faces the other ilium. Pelvic outlet IS the inferior margin of the true pelvis After the baby s head passes the inlet, the baby rotates to an anterio-posterior orientation with the forehead facing posteriorly

19 The Lower Limb The three segments of the lower limb are the thigh, leg, and foot They carry the weight of the erect body, and are subjected to exceptional forces when one jumps or runs

20 Femur The longest, largest, strongest bone of the body Articulates with the hip bone and knee Head: possesses the fovea capitis (central pit) Short ligament of the head of the femur runs from the fovea capitis to the acetabulum where it secures the femur The head is carried on a neck that angles laterally to join the body (the neck is the weakest part of the bone and is the location of a broken hip )

21 Femur Greater/lesser trochanters: Sites of attachment of the thigh and buttock muscles Other sites of muscle attachment are: The two trochanters are connected by the intertrochanteric line anteriorly and the intertrochanteric crest posteriorly The gluteal tuberosity blends into the linea aspera which diverges into the medial / lateral suprcondylar lines

22 Femur The lateral and medial condyles articulate with the tibia of the leg The medial and lateral epicondyles are sites of muscle attachment Adductor tubercle: site of muscle attachment Patellar surface: articulates with the patella (kneecap) Intercondylar fossa: Present between the condyles at the distal end of the femur. Articulates with the intercondylar eminence of the tibia Anterior and posterior intercondylar fossa (area) are the sites of anterior cruciate and posterior cruciate ligament attachment, respectively.

23 Tibia and Fibula Figure 7.29

24 Leg The tibia and fibula form the skeleton of the leg They are connected to each other by the interosseous membrane They articulate with the femur proximally and with the ankle bones distally They also articulate with each other proximally and distally via the immovable tibiofibular joints The tibiofibular joints allow essentially no movement. These joints are less flexible, but stronger than say the forearm Medial tibia articulates proximally with the femur to form the modified hinge joint of the knee and distally with the talus bone of the foot at the ankle Lateral portion of the fibula stabalizes the ankle joint

25 Tibia (shin bone) Receives the weight of the body from the femur and transmits it to the foot 2 nd largest, strongest bone in the body Medial and lateral condyles: articulate with the corresponding condyles of the femur and are separated by the intercondylar eminence Tibial tuberosity is the attachment site of the patellar ligament Tibial shaft is the triangular in cross-section The anterior and medial borders can be palpated The medial malleolus: a projection forming the medial bulge of the ankle Fibular notch: on the lateral surface. Participates in the distal tibiofibular joint

26 Fibula Head is the proximal end Lateral malleolus is the distal end (and results in the lateral ankle bulge) Articulates with the talus Does not bear weight, but is a site for muscle attachment

27 Foot The skeleton of the foot includes the tarsus, metatarsus, and the phalanges (toes) The foot supports body weight and acts as a lever to propel the body forward in walking and running Segmentation make the foot pliable for locomotion on uneven ground Figure 7.31a

28 Tarsus Figure 7.31b, c

29 Tarsus Composed of seven bones that form the posterior half of the foot Body weight is carried primarily on: the talus: articulates with the tibia and fibula superiorly The calcaneus: forms the heel and carries the talus on its superior surface. The calcaneal (Achilles) tendon attaches to the posterior surface of the calcaneus The calcaneus tuberosity is the part that touches the ground The sustentacalum tali (the talar shelf) is the part that supports the talus Tibia articulates with the talus at the trochlea of the talus The remaining tarsals are: Cubiod Navicular medial, intermediate, lateral cuneiform bones

30 Metatarsus and Phalanges Metatarsals Five (1-5) long bones that articulate with the proximal phalanges (Great Toe =1=medial) Articulate with cuboid and cuneiform bones of the tarsus and the proximal phalanges 1 st metatarsal plantar surface rests on 2 sesamoid bones (important for supporting body weight) e.g. ball of the feet Phalanges The 14 bones of the toes Arranged the same as the fingers Each digit has three phalanges except the hallux, which has no middle phalanx

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32 Arches of the Foot Figure 7.32

33 Arches of the Foot The arches are: Lateral longitudinal cuboid is keystone of this arch Medial longitudinal talus is keystone of this arch Transverse runs obliquely from one side of the foot to the other Maintained by strong ligaments and the pull of tendons Have a spring effect Medial longitudinal arch is very high compare (7.32 b to c) The talus and calcaneus bones form the high arch medially While the cuboid bone is key to the lateral arch 2 longitudinal arches serve as pillars for the transverse arch