BIO210 Weekly Guide #8
LOWER APPENDAGES;
MUSCULOSKELETAL DISORDERS
After completing this laboratory you should be able to:
1) Identify the bones of the lower extremity, as well as the major surface features of those bones
2) Identify the muscles of the lower extremity, providing the origin, insertion, and actions or each
3) Fully characterize the joints of the lower extremity
Guide to Gross Anatomy Guide to Histology Guide to Physiology
Outline
I. Lower Appendage Bones {FAP 8-3, 8-4}
A. Pelvic Girdle
sacrum
innominate
ilium
ischium
pubis
obturator foramen
greater and lesser sciatic notches/foramena
B. leg
femur
tibia
fibula
patella
C. Pes (foot)
tarsals
metatarsals
phalanges
II. Lower Appendage Joints {FAP 9-6, Table 9-3}
A. Hip
sacroiliac
inguinal
acetabulofemoral
B. Knee
C. Tibiofibular
proximal tibiofibular
interosseus
distal tibiofibular
D. Ankle and intertarsal
E. Tarsal-metatarsal
F. Metatarsal-phalangeal and interphalangeal joints
G. Arches
III. Lower Appendage Muscles {FAP 11-6}
A. Hip muscles
iliopsoas
gluteus group
lateral rotators
B. Muscles of the thigh
quadriceps
adductors
hamstrings
sartorius and tensor fascia latae
femoral triangle
C. Muscles of the leg, ankle, and foot
muscles of the tendocalcaneous
popliteus
dorsiflexor group
peroneus group
plantaflexor group
IV. Musculoskeletal Disorders {see PowerPoint}
A. Bone disorders
fractures and healing
rickets
B. Muscle disorders
muscular dystrophy
myasthenia gravis
C. Joints and soft tissue
bursitis
osteoarthritis
rheumatoid arthritis
ankylosis
Gross Anatomy List
Muscles of the Hip: Lower Extremity Bones:
Iliacus Gluteus Maximus innominate
Psoas Major Gluteus Medius ilium
Piriformis Gluteus Minimus ischium
Gemellus Superior Obturator Externus pubis
Gemellus Inferior Obturator Internus femur
Quadratus Femoris patella
tibia
Muscles of the Thigh: fibula
Quadriceps Group: tarsals (x7)
Rectus Femoris talus, calcaneus, navicular,
Vastus Lateralis cuboid, 3 cuneiforms
Vastus Intermedius metatarsals (x5)
Vastus Medialis phalanges (x14)
Hamstrings: sesamoid bones
Biceps Femoris - long & short heads
Semitendinosus Related Structures:
Semimembranosus Sacrospinous Ligament
Adductors: Sacrotuberous Ligament
Pectineus Obturator Foramen
Adductor Brevis Sciatic Foramina
Adductor Longus Inguinal Ligament
Adductor Magnus Fascia Lata
Gracilis Iliotibial Tract
Misc: Femoral Triangle
Sartorius Patellar Tendon
Tensor Fasciae Latae Menisci
Interosseus Ligament
Muscles of the Leg: Tendocalcaneus
Tibialis Anterior Transverse Arches
Extensor Digitorum Longus Longitudinal Arches
Extensor Hallucis Longus
Peroneus Longus
Peroneus Brevis
Gastrocnemius
Soleus
Plantaris
Tibialis Posterior
Flexor Digitorum Longus
Flexor Hallucis Longus
Popliteus
KEY: Know location, action, origin, & insertion (for muscles)
Know location & action (for muscles)
Not responsible for
Guide to Gross Anatomy
Lower Extremity Bones and Arthrology
The lower extremity bones are:
the pelvic girdle (innominate) - ilium, ischium, pubis
the thigh - femur
the knee-cap - patella ( a large sesamoid bone)
the leg - tibia, fibula
the ankle - 5 tarsals incl. talus, calcaneus
the foot - 5 metatarsals, 14 phalanges, sesamoids
a) The pelvic girdle {FAP Fig. 8-7 to 8-9, Spotlight 8-10; APL Figs. 8.25 to 8.27} consists of the two innominate bones, which together with the sacrum form the pelvis. Each innominate has three parts which form separately and fuse during puberty. On an innominate bone trace the approximate boundaries of the component bones and identify the following structures on each:
ilium:
iliac crest posterior superior iliac spine
anterior superior iliac spine auricular surface
anterior inferior iliac spine
ischium:
ischial spine ischial ramus lesser sciatic notch
ischial tuberosity greater sciatic notch
pubis:
pubic ramus symphysis pubis obturator foramen (pubis & ischium)
- The three bones meet and make up approximately equal thirds of the acetabulum, for hip socket. The easiest way to trace the boundaries of the bones is to start from the acetabulum and trace them outwards, like equal slices of a pie.
- What are the attachment points of the following three ligaments which help define and support the pelvic cavity: the inguinal ligament, the sacrospinous ligament, and the sacrotuberous ligament?
- Palpate the iliac crest from the posterior superior spine to the anterior superior spine.
- On an intact pelvis, trace the pelvic inlet and outlet. The "true" pelvis lies between these lines, while the "false" pelvis lies superior to the inlet.
- Develop a set of criteria which will allow you to unambiguously distinguish the pelvis of a female from that of a male. The following may help. The female pelvis (as compared to the male) has:
but "horizontal" internal ilac fossas
a "roomier" true pelvis
a shorter inlet to outlet distance
a wider subpelvic angle (approx. a right angle)
larger and wider sciatic notches
less inverted ischial spines and more everted ischial tuberosities
a straighter coccyx - not reliable for prepared skeletons
- A simpler composite criterion for distinguishing female and male pelvises is the following. Look straight into the pelvic inlet from above. If you see the outline of Minnie Mouse, it is a female. If you see the outline of Bugs Bunny, it is a male. Please do not EVER use this criterion on an exam answer.
- Fully classify the sacroiliac joints (both upper and lower portions). Fully classify the symphysis pubis.
b) Examine a femur {FAP Fig. 8-11; APL 8.28} and locate the following structures and regions:
head intertrochantric crest medial condyle
neck shaft lateral condyle
greater trochanter linea aspera medial epicondyle
lesser trochanter adductor tubercle lateral epicondyle
- Fully classify the hip joint. Note that it has a much more substantial socket than the shoulder, with much more stabilization by ligaments.
- Compare the hip and shoulder joint models. Why is it more difficult to dislocate your hip than your shoulder? Provide at least three structural reasons.
c) Examine a patella {FAP Fig. 8-11}. This is an example of a sesamoid bone. Sesamoid bones grow within a tendon and increase the leverage across the joint. Smaller sesamoid bones are found associated with the metacarpophalangeal joint of the thumb and the metatarsophalangeal joint of the great toe.
- Within what tendon is the patella found? What motion of the leg does it facilitate?
- Note the functional similarity between the patella and the olecranon of the ulna.
d) Examine a tibia and a fibula {FAP Fig. 8-13; APL Fig. 8.29} and locate the following structures and regions of the
tibia:
intercondylar eminence shaft
tibial tuberosity medial malleolus
fibula:
head shaft lateral malleolus
- Palpate the medial and lateral malleolus. Which is more distal?
- Fully classify the knee joint. What are the structure and function of the menisci?
e) The ankle and posterior (proximal) foot {FAP Fig. 8-14; APL 8.30} are made up of 7 tarsal bones. On a skeleton identify the two largest tarsal bones - the talus and calcaneus.
- With which bone(s) do the tibia and fibula articulate?
f) Study the foot {FAP Fig. 8-14; APL Fig. 8.30}. The anterior (distal) foot is made up of the 5 metatarsals and the 14 phalanges.
- Which bones comprise each of the three arches of the foot - the medial longitudinal, the lateral longitudinal, and the transverse?
Lower Extremity Muscles
The muscles of the lower extremity may be conveniently divided into those of the hip, thigh, and leg. We will not deal with the intrinsic muscles of the foot.
a) Hip muscles {FAP Fig. 11-20, Table 11-16; APL Figs.10.9, 19-15-10.18}. The muscles of the hip connect the pelvic girdle to the femur and act exclusively across the hip joint. The exception to this is the psoas major, which originates on the lumbar vertebrae and intervertebral disks. Study the origin, insertion, and action of the following:
psoas major gluteus minimus obturator internus
iliacus piriformis obturator externus
gluteus maximus gemellus superior quadratus femoris
gluteus medius gemellus inferior
- Which of these muscles are lateral rotators of the hip? Which are medial rotators? You may have trouble picturing the rotational action of some of these muscle (such as the psoas major) because prepared skeletons tend to have the femoral head displaced by an inch or so laterally.
- Which of these muscles are flexors of the thigh? Which are extensors?
b) Thigh muscles - miscellaneous{ FAP Figs. 11-20, 11-21, Table 11-16; APL Figs.10.17, 10.18}. The thigh muscles fall into three large groups based on location and action - the quadriceps (anterior), the hamstrings (posterior), and the adductors (medial). Two muscles don't fall into these groups. Study the origin, insertion, and action of the following:
sartorius tensor fasciae latae
- The sartorius is called the "tailor's" muscle because its action matches the sitting posture of a medieval tailor sewing. The easiest way to think of its several actions is to do the following. Sit in a chair with both feet on the floor. Now pick up your right foot and rest it on your left knee, so that your right calf is horizontal. Your right sartorius muscle participated in all of the motions you just performed.
- The fascia lata is a broad tendinous sheet which supports the heavy musculature of the anteriolateral thigh. Within this is a denser structure, the iliotibial tract. The tensor fasciae latae exerts its action primarily on this structure to "lock" the knee in its weight bearing position.
c) Thigh muscles - quadricep {FAP Fig. 11-20, Table 11-16; APL Figs.10.17, 10.18}. As the name suggests, the quadriceps group may be viewed as a four headed muscle with a common insertion - via the patellar tendon onto the tibial tuberosity. Study the origin, insertion, and action of the following:
rectus femoris vastus intermedius
vastus medialis vastus lateralis
- These muscles share what common action on the leg? The rectus femoris has what additional action on the thigh?
- What other two muscles share the origin point (anterior superior iliac spine) with the rectus femoris?
d) Thigh muscles - hamstrings {FAP Figs. 11-20, 11-21, Table 11-16; APL Figs.10.17, 10.18}. These are the principal extensors of the thigh and flexors of the leg. Study the origin, insertion, and action of the following:
semimembranosus semitendinosus biceps femoris (long and short heads)
- Which of these muscles originate on the ischial tuberosity and cross both the hip and knee joints? Which originates on the femur?
- Note the apparent redundancy in location and action of the semimembranosus and semitendinosus muscles. Actually the semitendinosus inserts more distally on the tibia and has the unique action of unlocking the knee joint at the beginning of each step.
e) Thigh muscles - adductors {FAP Figs. 11-20, 11-21, Table 11-16; APL Figs.10.17, 10.18}. These muscles all adduct the thigh. Study the origin, insertion, and action of the following:
pectineus adductor longus gracilis
adductor brevis adductor magnus
- Which of these muscles acts on the leg, as well as on the thigh?
- A convenient way to identify these muscles is to note that as you go from short to long, they alternate between relatively ventral (superficial) and dorsal (deep) origins, i.e. pectineus - ventral, adductor brevis - dorsal, adductor longus - ventral, adductor magnus - dorsal, and gracilis - ventral.
- The adductor longus, sartorius, and inguinal ligament frame an open region of the anterior thigh called the femoral triangle. The femoral artery, femoral vein, and femoral nerve travel superficially through the femoral triangle.
- The femoral artery, vein, and nerve exit the pelvis and enter the femoral triangle via the femoral ring, an opening deep to the inguinal canal. This creates yet another weak place in the abdominal wall and yet another type of hernia. Femoral hernias are more common in women than in men, presumably because men herniate more readily in the inguinal region.
f) Leg muscles {FAP Figs. 11-22, 11-23, Table 11-18; APL Figs.10.19, 10.20} fall into four convenient groups - anterior, lateral, posterior superficial, and posterior deep. Study the origin, insertion, and action of the following:
anterior group:
tibialis anterior extensor digitorum longus extensor hallucis longus
lateral group:
peroneus longus peroneus brevis
posterior superficial group:
gastrocnemius soleus
posterior deep group:
tibialis posterior flexor digitorum longus flexor hallucis longus
- Note that the anterior and posterior tibialis muscles act across the ankle joint. The flexor and extensor digitorum and hallucis muscles act additionally on (and derive their names from) the toes.
- Note that the peroneus (Greek) muscles are named for the fibula (Latin) from which they originate.
- Which muscle tendons pass immediately posterior to the medial malleolus? To the lateral malleolus?
- Note that the gastrocnemius and soleus muscles share a common insertion via the tendocalcaneus (Achilles' tendon). Upon which tarsal bone does this tendon insert? Which of these muscles crosses both the knee and ankle joints?
- Note that the theme of a deep muscle crossing a distal joint with an overlying superficial muscle also crossing a more proximal joint is repeated throughout the upper and lower extremities. Think of as many examples as you can.
Arthrology Review {FAP C 9; APL Unit 9}
Classify the joints of the lower appendage by degree of mobility, structure, and range of motion (for synovial joints).
Review of the Skeletomuscular System {FAP Chs 10, 11; APL Figs 8.3, 10.21, 10.22}
This concludes the presentation of the skeletomuscular system, with the exception of the head. It would be an extremely good idea to take some extra time at this point and review bones and muscles. One good way to do this is to work with a small group of people and go completely over a skeleton, asking each other questions such as:
What is the name of this bony process?
What muscles originate or insert here and what are their actions?
What is this action called, and what muscles do this?
What are synergists and antagonists for this action?
How would this joint be classified by movement? By structure?
Next, go to the available models and repeat the same kinds of questions.
Guide to Histology
There is no real histology this month.
Guide to Physiology
There is no real physiological component to this week's lab.