As a veterinary student, you might learn the details anatomical facts of the pig skeletal system. There are few osteological differences in domestic and wild pig skeletons. In this article, I will describe osteological features of different bones from pig skeleton.
I will try to cover all the exceptional characteristics of pig bones with a labeled diagram. After finishing this article, you will understand the differences in pig skeleton anatomy from other mammal’s skeleton.
Pig skeleton anatomy
First, I would like to provide you the most important and exceptional osteological features of pig skeleton anatomy. Then I will go through the detailed description of every bone from the pig skeletal system with a labeled diagram.
So what are the exceptions in the pig skeletal system? Fine, I will tell you the peculiarities of pig bones –
- The skull of a pig is elongated, and the occipital bone is hexagonal.
- There is an incomplete orbital ring in the pig skull.
- The cranial cavity is comparatively small.
- The cervical vertebrae are short, and bodies are wide, whereas thoracic vertebrae are comparatively long.
- There are six sternebrae fused to form the sternum of a pig.
- Pigs have fourteen to fifteen pairs of ribs, of which seven pairs are sternal, and the remaining seven to eight pairs are asternal.
- The acromion process is rudimentary, and no glenoid notch in pig scapula bone.
- Musculosprial groove is shallow, and there presence supratrochlear foramen at a distal end of the pig humerus bone.
- Radius of a pig is comparatively thin, and the ulna is massive bone.
- There are eight carpal bones in the carpus of a pig that arrange in two rows.
- The tuber sacralae of the hip bone is inclined caudally, and ischial tuberosity bears three prominences.
- The pig humerus is a more well-developed bone that posses a more curved head.
- There are no significant differences in the tibia fibula bones of pigs compare to other mammals.
- The tarsal bones are seven in number that arranged in three rows.
- There are four metatarsal bones in pig forelimb.
These osteological features are not enough to learn the pig skeletal system. You might know more features of different bones from pig skeleton.
Pig skull anatomy
Okay, let’s start with the skull of a pig. The length and shape of pig skull may vary with different pig species. Primarily, the skull of a pig is long elongated, especially in its fascial part. But the frontal part of the pig skull is almost straight. You will find the different pairs and unpairs bones in pig skull anatomy with few variations.
The occipital bone of the pig is flattened and elongated that forms the caudal part of the skull. Again the bacillary part of occipital bones is hexagonal, flattened caudally, and thicker rostrally. The squamous part of pig’s occipital bone is extensive, triangular, and flattened.
The zygomatic arch is strong and flattened side to side in a pig. There is a small and incomplete orbital cavity in the skull of a pig.
You will find a comparatively small cranial cavity in the pig skull due to the enormous development of frontal sinuses. The nasal cavity is long, presenting a visceral bone in the nasal septum (oss rostrale).
The presphenoid bone of a pig consists of a body and pairs of wings. You will find the ethmoid bone deep within the skull, in between the cranial and facial parts.
The maxilla bone of a pig is the main bone of the upper jaw and carries upper check teeth. Palatine bone locates on either side of the caudal nares of a pig. In the rostral margin of the bony orbit, there is an irregular lacrimal bone in the pig skull.
Now, I will show you the different bones with a diagram from the pig skeleton skull anatomy. If you want to know the features of these bones in detail, please read the article – pig skull anatomy.
Vertebrae from pig skeleton anatomy
While studying pig skeleton anatomy, you will find a lot of variations in their vertebrae. There are seven cervical vertebrae, fourteen to fifteen thoracic, six to seven lumbar, four sacral, and eighteen to twenty-five coccygeal vertebrae in pig skeletal anatomy. So, the vertebrae formula of a pig is quite different from other mammals.
Cervical vertebrae of pig
The cervical vertebrae of a pig are short and wide. Bodies of these cervical vertebrae are elliptical in cross-section. The cranial articular surfaces are highly convex from side to side and concave dorsoventrally.
There are two branches in the transverse processes of pig cervical vertebrae. From the third to sixth cervical vertebrae, the size of transverse processes increase. The spinous process of cervical vertebrae increases in height from the third to the last.
There is a large dorsal tubercle in the atlas. The ventral tubercle is long, compressed that project laterally back under the axis. The transverse process of pig’s atlas is flattened and posses a caudal tuberosity. Again the transverse foramen passes through the caudal border of the wing.
The axis of the pig has a large spinous process that directs dorsad and caudad. There is thick and cylindrical road-shaped dens in the pig axis. You will find a very small transverse process in the axis of a pig. The transverse foramen of the pig’s axis is incomplete.
Thoracic and Lumbar vertebrae from pig skeleton
From the pig skeleton anatomy, you may also find some osteological variation in the other vertebrae. The thoracic vertebrae of a pig are commonly fourteen or fifteen in number. Their bodies are relatively long and constricted in the middle.
You will not find any ventral crest in pig’s thoracic vertebrae.
In the arch of pig’s thoracic vertebrae, there presence two foramina. There are also lateral vertebral foramen in the caudal part in the root of transverse processes.
You will also find the mammillary process in the thoracic vertebrae of pig (except the first two). There is a long, plate-like transverse process in the last thoracic vertebrae. Small accessory processes may find in the caudal part of the thoracic vertebrae of a pig.
The spinous process of the pig’s first thoracic vertebrae is high, broad, and inclined cranially. Gradually the length of the spinous process decreases. From second to ninth, the spinous process inclines caudally.
There are six or seven lumbar vertebrae in the pig’s vertebral column. You will find the longer bodies and ventral crest in the pig’s lumbar vertebrae. The bodies of the lumbar vertebrae became wider and flattened at the caudal part.
You will find a deep notch at the caudal part of the lumbar vertebrae. The mammillary process projects lateral and caudad.
The transverse process bends ventrally and inclines cranially in pig’s lumbar vertebrae.
The spinous process of lumbar vertebrae is broad and inclines cranially. But the spinous process of the last lumbar vertebrae is narrow and verticle.
Sacrum and caudal vertebrae of pig
The sacrum of a pig usually consists of four vertebrae that fuse incompletely later. It is less curved and possesses a little developed spinous process. The dorsal surface of the pig’s sacrum is flattened and smooth that contains foramen.
You will find similar osteological features in some parts of the pig’s sacrum with an ox. The wing and the pelvic surface have similar osteological characteristics that of the ox. Cranial articular processes of the pig’s sacrum are very large.
In the first four caudal vertebrae, you will find functional articular processes. The remaining caudal vertebrae possess small and non-articular processes. The first five or six caudal vertebrae contain complete arches. You will find the broad and plate-like transverse processes in the cranial part of the series of caudal vertebrae.
Ribs and sternum from pig skeletal system
There are fourteen or fifteen pairs of ribs in the pig skeleton anatomy which seven are usually sternal, and others are asternal. The ribs of pigs are strongly curved that contain fairly distinct angles.
The first rib of a pig is prismatic and has a large ventral end and very short cartilage. You will find more width in the third to sixth ribs, whereas more in the sixth and seventh ribs. The tubercle fused with the head on the last five or six ribs of the pig.
The sternum of a pig consists of six segments that resemble that of the ox. The first segment is long, flattened laterally, and contains bluntly pointed cartilage on its cranial end. Other parts of the pig’s sternum are flattened, wide in its middle, and narrow at either end. The last segment of the pig’s sternum has a long, narrow xiphoid process that contains the xiphoid cartilage.
The forelimb of a pig skeleton
The forelimb or thoracic limb consists of four main parts – thoracic girdle, arm, forearm, and maneus. I will discuss every single bone from the thoracic limb of pig skeleton anatomy.
First, let’s discuss the bones from the thoracic girdle of pig anatomy.
Scapula of pig
The thoracic girdle of the pig consists of the flat scapula and short-fused coracoid processes. There is no clavicle in the thoracic girdle of a pig.
The scapula of a pig is a very well-developed, flattened bone in a pig that contains a very small and fused coracoid process. You will find a very wide and triangular spine on its lateral aspect that divides the scapula into two halves.
There is a large tuberosity at the middle wide part of the scapular spine. There is a rudimentary acromion process at the ventral aspect of the pig scapula.
The cranial border of the pig scapula is convex and thick, and rough in its middle. Caudal border is wide and slightly concave in a pig.
There is a narrow cranial angle found in the pig scapula that bends medially. Again the caudal angle of the scapula is thick. You will find a well-developed and round glenoid cavity. But there is no notch located in the glenoid cavity. At the craniomedial aspect of the glenoid cavity, there is a supraglenoid tubercle.
The humerus of pig skeleton anatomy
The body of the pig humerus is compressed side to slide. The medial surface of the humerus of a pig is extensive and flattened. You will not find any teres major tuberosity in the cranial surface of the pig humerus bone.
The musculospiral groove is shallow in pig humerus. There is a small deltoid tuberosity in the pig humerus. But you will find a large round prominence in between the deltoid and lateral tuberosity.
At the proximal part of the humerus of pig, you will also find the following features –
- A more strongly curved head
- Larger greater tubercle
There is an undivided intertuberal groove at the front of the medial aspect of the humerus. The olecranon fossa is very deep and a plate of the bone in a pig.
Radius ulna and maneus of pig
The radius is a short, narrow but thick bone in the pig skeleton anatomy. At the caudal surface, you will find the ulna bone. A large vascular furrow runs distally from the proximal part of the caudal surface of the radius bone. The distal end of the trochlea is relatively large in a pig.
The ulna is a massive and much longer and heavier bone than the radius bone. The cranial surface is convex, and most of it is rough and attached to the radius bone by the interosseous ligament. Lateral surface of the ulna bone is slightly convex and posses an oblique irregular line. Again, the medial surface is concave, extensive, and smooth in a pig.
The carpus consists of eight bones, four in each row. There are four metacarpal bones found in the pig. The first metacarpal is absent in pig, and the third and fourth are larger.
These third and fourth metacarpal bones of a pig are flattened from dorsal to palmar and are three-sided bones.
Each main digits of a pig possess three phalanges and three sesamoid bones.
The bones of the main digit resemble those of the ox in form. But there is no foramen on the axial surface of the extensor process.
Bones from the pelvic limb of a pig skeleton
The pelvic limb also consists of four parts – pelvic girdle, thigh, leg, and pes. I will also show you every single bone from the pelvic limb or hindlimb from the pig skeleton.
Ox coxae of pig
The pelvic girdle of a pig consists of os coxarum and the sacrum. You know the os coxarum consists of the os coxae of both sides that join with pelvic symphysis. Again the pelvic symphysis consists of the pubic symphysis and ischiatic symphysis.
The os coxae of a pig is narrow and long. Ilium and ischium bones are in line with each other. The ilium bone is not much extended laterally. The gluteal surface divides into two fossae by the ridge that continues with the ischiatic spine.
Again the sacropelvic surface posses an extensive rough area caudally. There is a convex and thick crest that becomes rough and prominent in its middle portion. The tuber sacralae is lower than the crest and directed caudally.
In the female, the floor of the pelvic is much wider and flattened. The ischial arch is wide, and the pubis bone is thicker in a pig.
There are three prominences in the ischial tuberosity of pig os coxae. The rim of the acetabulum is much thicker in a pig.
A femur from pig skeleton
The femur is a relatively wide and massive bone in pig skeleton that consists of four different surfaces. You will find the nutrient foramen at the proximal third of the cranial surface of the femur. The caudal surface of the femur is wide and limited laterally by a ridge.
There are greater trochanter and lateral supracondyloid tuberosity at the caudal aspect of the femur. The greater trochanter does not extend above the level of the head.
You will not find any supracondyloid fossa in the femur of a pig. The head of the femur is strongly curved and is marked towards the medial side.
The intertrochanteric crest and the trochanteric fossa resemble those of the ox. There is no third trochanter in the femur of a pig.
The patella of a pig is very much compressed transversely and posses three surfaces. You will find a detailed guide on the structure of the animal patella here in anatomy learner.
Tibia fibula and pes of pig
The tibia is a slightly curved bone in a pig skeleton. You will find a groove in the tibial tuberosity of the pig. The proximal part of the cranial border of tibia is very prominent and curved laterally. There is a narrow and thicker distal end in the pig femur.
The fibula of the pig extends the entire length of the region and remains separate from the tibia by a wide interosseous space. The body of the pig’s fibula bone is flattened side by side.
There is a wide, grooved proximal end in the fibula that articulates medially with the lateral condyle of the tibia. The distal end of the fibula posses lateral malleolus. There is a groove in the distal end of the
fibula bone and articulates with tibia and talus medially.
You will find seven tarsal bones in a pig. The talas and calcaneus resemble those of the ox. There presence a double trochlea at the distal end of the talus for the articulation with the central and fourth tarsal bones. The calcaneus tuber is a deeply grooved planter.
The first tarsal is high and narrow, articulating with the central and second tarsal and the second metatarsal bone. The second tarsal is small and somewhat prismatic in a pig. There is a large and compressed third tarsal found in the pig skeletal system anatomy.
You will find four metatarsal bones in a pig. The third and fourth metacarpal bones have a large planter projection.
The second and fourth metatarsal bones place more towards the plantar aspect.
You will find similar osteological features in the phalanges of the hindlimb as those of the hindlimb of a pig. The proximal and middle phalanges are longer and narrower than those of the forelimb of a pig.
Pig skeleton labeled diagram
Okay, let’s try to summarize the exceptional features of pig bones. I want to suggest you again identify all these bones from the pig skeletal system with the help of a labeled diagram.
If you need more pig skeleton labeled diagrams, please let me know. I will try to provide more labeled diagrams for pig bones. Or you may follow anatomy learn on social media for more pig’s bones labeled diagram.
Frequently asked question on pig bones
So, in this part of the article, you may find your desire question on pig bone anatomy.
What type of skeleton does a pig have?
The pig has both the axial skeleton and appendicular skeleton, as found in the ox skeleton anatomy. But the number of bones in the skeleton may vary with different domestic pig and wild pig species.
What is a chicken skeleton?
I have a detailed guide on chicken skeletons here on anatomy learn. There presence exceptional pneumatic bones in the chicken skeleton. For details, please go to the avian anatomy section and read these articles.
Do pigs have ankles?
Yes, pigs have ankles. You will find seven bones that form the ankle joint with tibia fibula bones.
How many bones are in the pig?
The number of bones may vary in different species of pig. But ideally, you may find a total of 270 bones in a pig skeleton.
How many bones does a pig’s neck have?
There are 7 (seven) bones in the neck of a pig. There are atlas, axis, third cervical to seventh cervical bones in the pig’s neck.
Does pig have veins in their leg?
Yes, there are veins in the pig leg.
Does pig have teeth?
Yes, pigs have teeth. They have 44 permanent teeth. In male pigs, the canine teeth are well developed. The canine teeth of the pig’s upper jaw is curved laterally and dorsally.
I hope this simple guide on pig skeleton anatomy will help you identify the special osteological features of different bones. Please get more help from the pig skeletal system model and labeled diagrams. Now, you might try to identify the pig bones physically from the anatomy learning laboratory.