LEA - Osteology

Question 1

name the vertebral structure that matches with its corrsesponding fused sacral structure

Answer 1

Question 2

what is the difference between the pelvic girdle and the bony pelvis?

Answer 2

• pelvic girdle: ilium, ischium, & pubis
• bony pelvis: pelvic girdle + sacrum & coccyx

the pelvic girdle and its components are part of the the appendicular skeleton, while the sacrum and coccyx are part of the axial skeleton

Question 3

which pelvic bone is the FIRST to fuse?

Answer 3

pubis (8 years)

• followed by the ilium (16-23 years) and ischium (17-25 years).*
• Remember to reveiw ossification charts and commit to memory!*

Question 4

the iliopectineal line is made by which two bony landmarks?

Answer 4

pectin pubis (pubis) & arcuate line (ilium)

Add on the sacral promontory and you have the “linea terminalis”

Question 5

which bone contains the anterior, posterior, and inferior gluteal lines?

Answer 5

ilium

these lines mark the areas of origin of the gluteal muscles:

• gluteus maximus - posterior to the posterior gluteal line
• gluteus medius - between the posterior and anterior gluteal lines
• gluteus minimus - between the anterior and inferior gluteal lines

Question 6

what parts of what bones make up the acetabulum of the pelvis?

Answer 6

1. body of ilium
2. body of ischium
3. superior ramus of the pubis

Question 7

what ligament attaches to the pubic tubercle?

Answer 7

the inguinal (aka Pourpart’s) ligament

• this important ligament runs from the anterior superior iliac spine (ASIS) to the pubic tubercle.*
• Review the important structures that pass beneath inguinal ligament, or see in landmarks section*

Question 8

what bones form the obturator foramen?

Answer 8

pubis & ischium

the obturator nerve, artery, and vein traverse this foramen to exit the pelvis

Question 9

what area of the ischial tuberosity is devoid of muscular origin?

Answer 9

sitz platz

• this is part of the tuberosity that is exposed when sitting. It is located on the inferomedial aspect of the tuberosity.*
• Refer to card #184 in landmarks for more info. on muscular origins from the ischial tuberosity*

Question 10

name the order in which the secondary ossification centers of the femur begin to ossify and then fuse

Answer 10

Question 11

what is the femoral angle of inclination?

Answer 11

also known as the “Q” angle, it is made by the longitudinal axis of the femoral shaft and a line perpendicular to the ground.

Normal is 10-15 degrees in adults

Question 12

what is the femoral angle of torsion (declination)?

Answer 12

angle made by the longitudinal axis of the femoral neck and the femoral condyles in the frontal plane.

normal is 10-15 degrees in adults (higher in children)

Question 13

what lines contribute to the formation of the linea aspera?

Answer 13

• medial lip: spiral line + pectineal line
• lateral lip: gluteal tuberosity

The linea aspera comprises the posterior border of the femoral shaft that divides its medial and lateral surfaces. It terminates as the medial and lateral supracondylar ridges at the distal shaft to create the triangular popliteal surface

Question 14

what is the inherently weak portion of the femoral neck called?

Answer 14

ward’s triangle;

(aka the internal femoral triangle)

Question 15

name the muscles that insert into the bony structures on the proximal femur

Answer 15

Question 16

where is the adductor tubercle of the femur located?

Answer 16

at the termination of the medial supracondylar ridge on the posterior aspect of the femoral shaft

it serves as the insertion for the adductor portion of the adductor magnus muscle

Question 17

how do you “side” a patella?

Answer 17

the lateral facet on the posterior surface will be larger than the medial facet, which can help you determine if it came from the left or the right lower extremity

the patella is the largest sesamoid in the body; it acts as a fulcrum for the quadriceps tendon during extension. It ossifies at 3-6 years of age

Question 18

when does the primary center of ossification appear for the long bones of the thigh and leg?

Answer 18

femur: week 7 of gestation
tibia: week 7-8 of gestation
fibular: weeks 8-9 of gestation
* for all 3, the primary center is located in the DIAPHYSIS*

Question 19

describe the order of appearance of the secondary ossification centers in the leg

Answer 19

• proximal tibial epiphysis: birth
• distal tibial epiphysis: 3-10 months old
• distal fibular epiphysis: 9-22 months old
• proximal fibular epiphysis: 3-5 yrs old

Trick: Proximal to distal, distal to proximal with the tibia coming first

Question 20

what is the angle used to describe in-toeing of the foot due to the tibia?

Answer 20

tibial torsion,

• this angle is made by two lines in the transverse plane. One is made from medial to lateral across the tibial plateau. The other connects the malleoli*
• as an infant, tibial torsion causes the foot to take on an in-toed appearance. this angle increases trhoughout development, moving away from the in-toed position to a more neutral or even out-toed one*

Question 21

what inserts into Gerdy’s tubercle?

Answer 21

iliotibial (IT) band

• the tensor fascia lata and gluteus maximus insert into the IT band.*
• Gerdy’s tubercle is located at the lateral condyle of the tibia anteriorly*

Question 22

what parts of the tibia and fibula are subcutaneous?

Answer 22

• tibia: anterior border (shin), medial surface (no muscular attachments), medial malleolus
• fibula: head of the fibula, distal triangular part of anterior border, lateral malleolus

Since these structures are subcutaneous, they are also palpable

Question 23

the tendons of what muscles travel in the medial and lateral malleolar sulci?

Answer 23

Question 24

name the bones that make up the medial longitudinal arch of the foot

Answer 24

Question 25

name the bones that make up the TRANSVERSE arch of the foot

Answer 25

cuneiforms & cuboid

this arch is formed by the midfoot bones, minus the navicular. the intermediate cuneiform acts as its apex

Question 26

the posterior tubercles of the talus create a groove for what muscle tendon?

Answer 26

flexor hallucis longus (FHL)

• the lateral tubercle may fail to fuse and remain as an accessory bone known as the os trigonum.*
• the FHL tendon’s course continues into the plantar aspect of the foot via the sustentaculum tali of the calcaneus*

Question 27

name the muscles that arise from the plantar calcaneus

Answer 27

• abductor hallucis (AbH)
• flexor digitorum brevis (FDB)
• quadratus plantae
• abductor digiti minimi

Question 28

the peroneal sulcus is found on what bone of the tarsus?

Answer 28

Question 29

what is the accessory bone of the navicular known as?

Answer 29

os tibiale externum

Question 30

which two muscles have insertions into both the medial cuneiform and first metatarsal?

Answer 30

1. tibialis anterior (medial and plantar)
2. peroneus longus (lateral and plantar)

Question 31

which bone(s) of the foot are the last to ossify?

Answer 31

sesamoids (10-12 yrs)

• these accessory bones are found in the medial and lateral heads of the flexor hallucis brevis tendons.*
• they are commonly referred to as the tibial (medial) and fibular (lateral) sesamoids*

Question 32

at birth, which bones of the foot have not yet begun to ossify?

Answer 32

Question 33

on which surface of each metatarsal shaft do the nutrient arteries most commonly enter?

Answer 33

Question 34

describe the rotational changes the talus undergoes in the frontal and transverse planes during development

Answer 34